diff --git a/coordinator/coordinator.lua b/coordinator/coordinator.lua
index 094bf5b..e6c7671 100644
--- a/coordinator/coordinator.lua
+++ b/coordinator/coordinator.lua
@@ -520,7 +520,7 @@ function coordinator.comms(version, nic, sv_watchdog)
                 if self.sv_r_seq_num == nil then
                     self.sv_r_seq_num = packet.scada_frame.seq_num() + 1
                 elseif self.sv_r_seq_num ~= packet.scada_frame.seq_num() then
-                    log.warning("sequence out-of-order: last = " .. self.sv_r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
+                    log.warning("sequence out-of-order: next = " .. self.sv_r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
                     return false
                 elseif self.sv_linked and src_addr ~= self.sv_addr then
                     log.debug("received packet from unknown computer " .. src_addr .. " while linked; channel in use by another system?")
diff --git a/coordinator/session/pocket.lua b/coordinator/session/pocket.lua
index c554c64..5b5e7ce 100644
--- a/coordinator/session/pocket.lua
+++ b/coordinator/session/pocket.lua
@@ -106,7 +106,7 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout)
     local function _handle_packet(pkt)
         -- check sequence number
         if self.r_seq_num ~= pkt.scada_frame.seq_num() then
-            log.warning(log_header .. "sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
+            log.warning(log_header .. "sequence out-of-order: next = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
             return
         else
             self.r_seq_num = pkt.scada_frame.seq_num() + 1
@@ -186,6 +186,10 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout)
             elseif pkt.type == MGMT_TYPE.CLOSE then
                 -- close the session
                 _close()
+            elseif pkt.type == MGMT_TYPE.ESTABLISH then
+                -- something is wrong, kill the session
+                _close()
+                log.warning(log_header .. "terminated session due to an unexpected ESTABLISH packet")
             else
                 log.debug(log_header .. "handler received unsupported SCADA_MGMT packet type " .. pkt.type)
             end
diff --git a/coordinator/startup.lua b/coordinator/startup.lua
index cb7d92b..8fb6173 100644
--- a/coordinator/startup.lua
+++ b/coordinator/startup.lua
@@ -19,7 +19,7 @@ local renderer    = require("coordinator.renderer")
 local sounder     = require("coordinator.sounder")
 local threads     = require("coordinator.threads")
 
-local COORDINATOR_VERSION = "v1.5.5"
+local COORDINATOR_VERSION = "v1.5.6"
 
 local CHUNK_LOAD_DELAY_S = 30.0
 
diff --git a/pocket/pocket.lua b/pocket/pocket.lua
index 5ca6349..dc9fa28 100644
--- a/pocket/pocket.lua
+++ b/pocket/pocket.lua
@@ -610,7 +610,7 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog, nav)
                 if self.api.r_seq_num == nil then
                     self.api.r_seq_num = packet.scada_frame.seq_num() + 1
                 elseif self.api.r_seq_num ~= packet.scada_frame.seq_num() then
-                    log.warning("sequence out-of-order (API): last = " .. self.api.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
+                    log.warning("sequence out-of-order (API): next = " .. self.api.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
                     return
                 elseif self.api.linked and (src_addr ~= self.api.addr) then
                     log.debug("received packet from unknown computer " .. src_addr .. " while linked (API expected " .. self.api.addr ..
@@ -697,24 +697,24 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog, nav)
                                 else
                                     log.debug("received coordinator establish allow without facility configuration")
                                 end
-                            elseif est_ack == ESTABLISH_ACK.DENY then
-                                if self.api.last_est_ack ~= est_ack then
-                                    log.info("coordinator connection denied")
-                                end
-                            elseif est_ack == ESTABLISH_ACK.COLLISION then
-                                if self.api.last_est_ack ~= est_ack then
-                                    log.info("coordinator connection denied due to collision")
-                                end
-                            elseif est_ack == ESTABLISH_ACK.BAD_VERSION then
-                                if self.api.last_est_ack ~= est_ack then
-                                    log.info("coordinator comms version mismatch")
-                                end
-                            elseif est_ack == ESTABLISH_ACK.BAD_API_VERSION then
-                                if self.api.last_est_ack ~= est_ack then
-                                    log.info("coordinator api version mismatch")
-                                end
                             else
-                                log.debug("coordinator SCADA_MGMT establish packet reply unsupported")
+                                if self.api.last_est_ack ~= est_ack then
+                                    if est_ack == ESTABLISH_ACK.DENY then
+                                        log.info("coordinator connection denied")
+                                    elseif est_ack == ESTABLISH_ACK.COLLISION then
+                                        log.info("coordinator connection denied due to collision")
+                                    elseif est_ack == ESTABLISH_ACK.BAD_VERSION then
+                                        log.info("coordinator comms version mismatch")
+                                    elseif est_ack == ESTABLISH_ACK.BAD_API_VERSION then
+                                        log.info("coordinator api version mismatch")
+                                    else
+                                        log.debug("coordinator SCADA_MGMT establish packet reply unsupported")
+                                    end
+                                end
+
+                                -- unlink
+                                self.api.addr = comms.BROADCAST
+                                self.api.linked = false
                             end
 
                             self.api.last_est_ack = est_ack
@@ -730,7 +730,7 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog, nav)
                 if self.sv.r_seq_num == nil then
                     self.sv.r_seq_num = packet.scada_frame.seq_num() + 1
                 elseif self.sv.r_seq_num ~= packet.scada_frame.seq_num() then
-                    log.warning("sequence out-of-order (SVR): last = " .. self.sv.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
+                    log.warning("sequence out-of-order (SVR): next = " .. self.sv.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
                     return
                 elseif self.sv.linked and (src_addr ~= self.sv.addr) then
                     log.debug("received packet from unknown computer " .. src_addr .. " while linked (SVR expected " .. self.sv.addr ..
@@ -831,20 +831,22 @@ function pocket.comms(version, nic, sv_watchdog, api_watchdog, nav)
                                 else
                                     iocontrol.report_link_state(LINK_STATE.SV_LINK_ONLY, self.sv.addr, nil)
                                 end
-                            elseif est_ack == ESTABLISH_ACK.DENY then
-                                if self.sv.last_est_ack ~= est_ack then
-                                    log.info("supervisor connection denied")
-                                end
-                            elseif est_ack == ESTABLISH_ACK.COLLISION then
-                                if self.sv.last_est_ack ~= est_ack then
-                                    log.info("supervisor connection denied due to collision")
-                                end
-                            elseif est_ack == ESTABLISH_ACK.BAD_VERSION then
-                                if self.sv.last_est_ack ~= est_ack then
-                                    log.info("supervisor comms version mismatch")
-                                end
                             else
-                                log.debug("supervisor SCADA_MGMT establish packet reply unsupported")
+                                if self.sv.last_est_ack ~= est_ack then
+                                    if est_ack == ESTABLISH_ACK.DENY then
+                                        log.info("supervisor connection denied")
+                                    elseif est_ack == ESTABLISH_ACK.COLLISION then
+                                        log.info("supervisor connection denied due to collision")
+                                    elseif est_ack == ESTABLISH_ACK.BAD_VERSION then
+                                        log.info("supervisor comms version mismatch")
+                                    else
+                                        log.debug("supervisor SCADA_MGMT establish packet reply unsupported")
+                                    end
+                                end
+
+                                -- unlink
+                                self.sv.addr = comms.BROADCAST
+                                self.sv.linked = false
                             end
 
                             self.sv.last_est_ack = est_ack
diff --git a/pocket/startup.lua b/pocket/startup.lua
index ed3f36f..d548b73 100644
--- a/pocket/startup.lua
+++ b/pocket/startup.lua
@@ -20,7 +20,7 @@ local pocket    = require("pocket.pocket")
 local renderer  = require("pocket.renderer")
 local threads   = require("pocket.threads")
 
-local POCKET_VERSION = "v0.11.6-alpha"
+local POCKET_VERSION = "v0.11.7-alpha"
 
 local println = util.println
 local println_ts = util.println_ts
diff --git a/reactor-plc/plc.lua b/reactor-plc/plc.lua
index 5300bd9..36cb8ed 100644
--- a/reactor-plc/plc.lua
+++ b/reactor-plc/plc.lua
@@ -833,7 +833,7 @@ function plc.comms(version, nic, reactor, rps, conn_watchdog)
             if self.r_seq_num == nil then
                 self.r_seq_num = packet.scada_frame.seq_num() + 1
             elseif self.r_seq_num ~= packet.scada_frame.seq_num() then
-                log.warning("sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
+                log.warning("sequence out-of-order: next = " .. self.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
                 return
             elseif self.linked and (src_addr ~= self.sv_addr) then
                 log.debug("received packet from unknown computer " .. src_addr .. " while linked (expected " .. self.sv_addr ..
diff --git a/reactor-plc/startup.lua b/reactor-plc/startup.lua
index b83f9df..f1cdae2 100644
--- a/reactor-plc/startup.lua
+++ b/reactor-plc/startup.lua
@@ -18,7 +18,7 @@ local plc       = require("reactor-plc.plc")
 local renderer  = require("reactor-plc.renderer")
 local threads   = require("reactor-plc.threads")
 
-local R_PLC_VERSION = "v1.8.5"
+local R_PLC_VERSION = "v1.8.6"
 
 local println = util.println
 local println_ts = util.println_ts
diff --git a/rtu/rtu.lua b/rtu/rtu.lua
index ae09b01..daf9f22 100644
--- a/rtu/rtu.lua
+++ b/rtu/rtu.lua
@@ -444,7 +444,7 @@ function rtu.comms(version, nic, conn_watchdog)
             if self.r_seq_num == nil then
                 self.r_seq_num = packet.scada_frame.seq_num() + 1
             elseif self.r_seq_num ~= packet.scada_frame.seq_num() then
-                log.warning("sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
+                log.warning("sequence out-of-order: next = " .. self.r_seq_num .. ", new = " .. packet.scada_frame.seq_num())
                 return
             elseif rtu_state.linked and (src_addr ~= self.sv_addr) then
                 log.debug("received packet from unknown computer " .. src_addr .. " while linked (expected " .. self.sv_addr ..
diff --git a/rtu/startup.lua b/rtu/startup.lua
index cbaada7..b978164 100644
--- a/rtu/startup.lua
+++ b/rtu/startup.lua
@@ -31,7 +31,7 @@ local sna_rtu      = require("rtu.dev.sna_rtu")
 local sps_rtu      = require("rtu.dev.sps_rtu")
 local turbinev_rtu = require("rtu.dev.turbinev_rtu")
 
-local RTU_VERSION = "v1.10.5"
+local RTU_VERSION = "v1.10.6"
 
 local RTU_UNIT_TYPE = types.RTU_UNIT_TYPE
 local RTU_UNIT_HW_STATE = databus.RTU_UNIT_HW_STATE
diff --git a/supervisor/session/coordinator.lua b/supervisor/session/coordinator.lua
index a135a44..99aa027 100644
--- a/supervisor/session/coordinator.lua
+++ b/supervisor/session/coordinator.lua
@@ -53,7 +53,7 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
     -- print a log message to the terminal as long as the UI isn't running
     local function println(message) if not fp_ok then util.println_ts(message) end end
 
-    local log_header = "crdn_session(" .. id .. "): "
+    local log_tag = "crdn_session(" .. id .. "): "
 
     local self = {
         units = facility.get_units(),
@@ -184,7 +184,7 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
     local function _handle_packet(pkt)
         -- check sequence number
         if self.r_seq_num ~= pkt.scada_frame.seq_num() then
-            log.warning(log_header .. "sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
+            log.warning(log_tag .. "sequence out-of-order: next = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
             return
         else
             self.r_seq_num = pkt.scada_frame.seq_num() + 1
@@ -205,7 +205,7 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
                     self.last_rtt = srv_now - srv_start
 
                     if self.last_rtt > 750 then
-                        log.warning(log_header .. "COORD KEEP_ALIVE round trip time > 750ms (" .. self.last_rtt .. "ms)")
+                        log.warning(log_tag .. "COORD KEEP_ALIVE round trip time > 750ms (" .. self.last_rtt .. "ms)")
                     end
 
                     -- log.debug(log_header .. "COORD RTT = " .. self.last_rtt .. "ms")
@@ -213,13 +213,17 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
 
                     databus.tx_crd_rtt(self.last_rtt)
                 else
-                    log.debug(log_header .. "SCADA keep alive packet length mismatch")
+                    log.debug(log_tag .. "SCADA keep alive packet length mismatch")
                 end
             elseif pkt.type == MGMT_TYPE.CLOSE then
                 -- close the session
                 _close()
+            elseif pkt.type == MGMT_TYPE.ESTABLISH then
+                -- something is wrong, kill the session
+                _close()
+                log.warning(log_tag .. "terminated session due to an unexpected ESTABLISH packet")
             else
-                log.debug(log_header .. "handler received unsupported SCADA_MGMT packet type " .. pkt.type)
+                log.debug(log_tag .. "handler received unsupported SCADA_MGMT packet type " .. pkt.type)
             end
         elseif pkt.scada_frame.protocol() == PROTOCOL.SCADA_CRDN then
             ---@cast pkt crdn_frame
@@ -252,7 +256,7 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
 
                             _send(CRDN_TYPE.FAC_CMD, { cmd, table.unpack(facility.auto_start(config)) })
                         else
-                            log.debug(log_header .. "CRDN auto start (with configuration) packet length mismatch")
+                            log.debug(log_tag .. "CRDN auto start (with configuration) packet length mismatch")
                         end
                     elseif cmd == FAC_COMMAND.ACK_ALL_ALARMS then
                         facility.ack_all()
@@ -261,25 +265,25 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
                         if pkt.length == 2 then
                             _send(CRDN_TYPE.FAC_CMD, { cmd, facility.set_waste_product(pkt.data[2]) })
                         else
-                            log.debug(log_header .. "CRDN set waste mode packet length mismatch")
+                            log.debug(log_tag .. "CRDN set waste mode packet length mismatch")
                         end
                     elseif cmd == FAC_COMMAND.SET_PU_FB then
                         if pkt.length == 2 then
                             _send(CRDN_TYPE.FAC_CMD, { cmd, facility.set_pu_fallback(pkt.data[2]) })
                         else
-                            log.debug(log_header .. "CRDN set pu fallback packet length mismatch")
+                            log.debug(log_tag .. "CRDN set pu fallback packet length mismatch")
                         end
                     elseif cmd == FAC_COMMAND.SET_SPS_LP then
                         if pkt.length == 2 then
                             _send(CRDN_TYPE.FAC_CMD, { cmd, facility.set_sps_low_power(pkt.data[2]) })
                         else
-                            log.debug(log_header .. "CRDN set sps low power packet length mismatch")
+                            log.debug(log_tag .. "CRDN set sps low power packet length mismatch")
                         end
                     else
-                        log.debug(log_header .. "CRDN facility command unknown")
+                        log.debug(log_tag .. "CRDN facility command unknown")
                     end
                 else
-                    log.debug(log_header .. "CRDN facility command packet length mismatch")
+                    log.debug(log_tag .. "CRDN facility command packet length mismatch")
                 end
             elseif pkt.type == CRDN_TYPE.UNIT_BUILDS then
                 -- acknowledgement to coordinator receiving builds
@@ -307,13 +311,13 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
                             if pkt.length == 3 then
                                 out_queue.push_data(SV_Q_DATA.SET_BURN, data)
                             else
-                                log.debug(log_header .. "CRDN unit command burn rate missing option")
+                                log.debug(log_tag .. "CRDN unit command burn rate missing option")
                             end
                         elseif cmd == UNIT_COMMAND.SET_WASTE then
                             if (pkt.length == 3) and (type(pkt.data[3]) == "number") and (pkt.data[3] > 0) and (pkt.data[3] <= 4) then
                                 unit.set_waste_mode(pkt.data[3])
                             else
-                                log.debug(log_header .. "CRDN unit command set waste missing/invalid option")
+                                log.debug(log_tag .. "CRDN unit command set waste missing/invalid option")
                             end
                         elseif cmd == UNIT_COMMAND.ACK_ALL_ALARMS then
                             unit.ack_all()
@@ -322,32 +326,32 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
                             if pkt.length == 3 then
                                 unit.ack_alarm(pkt.data[3])
                             else
-                                log.debug(log_header .. "CRDN unit command ack alarm missing alarm id")
+                                log.debug(log_tag .. "CRDN unit command ack alarm missing alarm id")
                             end
                         elseif cmd == UNIT_COMMAND.RESET_ALARM then
                             if pkt.length == 3 then
                                 unit.reset_alarm(pkt.data[3])
                             else
-                                log.debug(log_header .. "CRDN unit command reset alarm missing alarm id")
+                                log.debug(log_tag .. "CRDN unit command reset alarm missing alarm id")
                             end
                         elseif cmd == UNIT_COMMAND.SET_GROUP then
                             if (pkt.length == 3) and (type(pkt.data[3]) == "number") and (pkt.data[3] >= 0) and (pkt.data[3] <= 4) then
                                 facility.set_group(unit.get_id(), pkt.data[3])
                                 _send(CRDN_TYPE.UNIT_CMD, { cmd, uid, pkt.data[3] })
                             else
-                                log.debug(log_header .. "CRDN unit command set group missing group id")
+                                log.debug(log_tag .. "CRDN unit command set group missing group id")
                             end
                         else
-                            log.debug(log_header .. "CRDN unit command unknown")
+                            log.debug(log_tag .. "CRDN unit command unknown")
                         end
                     else
-                        log.debug(log_header .. "CRDN unit command invalid")
+                        log.debug(log_tag .. "CRDN unit command invalid")
                     end
                 else
-                    log.debug(log_header .. "CRDN unit command packet length mismatch")
+                    log.debug(log_tag .. "CRDN unit command packet length mismatch")
                 end
             else
-                log.debug(log_header .. "handler received unexpected SCADA_CRDN packet type " .. pkt.type)
+                log.debug(log_tag .. "handler received unexpected SCADA_CRDN packet type " .. pkt.type)
             end
         end
     end
@@ -370,7 +374,7 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
         _close()
         _send_mgmt(MGMT_TYPE.CLOSE, {})
         println("connection to coordinator " .. id .. " closed by server")
-        log.info(log_header .. "session closed by server")
+        log.info(log_tag .. "session closed by server")
     end
 
     -- iterate the session
@@ -437,14 +441,14 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
                                 _send(CRDN_TYPE.FAC_BUILDS, { facility.get_build(cmd.val.type) })
                             end
                         else
-                            log.error(log_header .. "unsupported data command received in in_queue (this is a bug)", true)
+                            log.error(log_tag .. "unsupported data command received in in_queue (this is a bug)", true)
                         end
                     end
                 end
 
                 -- max 100ms spent processing queue
                 if util.time() - handle_start > 100 then
-                    log.warning(log_header .. "exceeded 100ms queue process limit")
+                    log.warning(log_tag .. "exceeded 100ms queue process limit")
                     break
                 end
             end
@@ -452,7 +456,7 @@ function coordinator.new_session(id, s_addr, i_seq_num, in_queue, out_queue, tim
             -- exit if connection was closed
             if not self.connected then
                 println("connection to coordinator closed by remote host")
-                log.info(log_header .. "session closed by remote host")
+                log.info(log_tag .. "session closed by remote host")
                 return self.connected
             end
 
diff --git a/supervisor/session/plc.lua b/supervisor/session/plc.lua
index 301e9b3..f0394e0 100644
--- a/supervisor/session/plc.lua
+++ b/supervisor/session/plc.lua
@@ -58,7 +58,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
     -- print a log message to the terminal as long as the UI isn't running
     local function println(message) if not fp_ok then util.println_ts(message) end end
 
-    local log_header = "plc_session(" .. id .. "): "
+    local log_tag = "plc_session(" .. id .. "): "
 
     local self = {
         commanded_state = false,
@@ -184,7 +184,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
         self.sDB.max_op_temp_H2O = max_burn * 2 * (JOULES_PER_MB * heat_cap ^ -1) + BASE_BOIL_TEMP
         self.sDB.max_op_temp_Na = max_burn * (JOULES_PER_MB * heat_cap ^ -1) + BASE_BOIL_TEMP
 
-        log.info(util.sprintf(log_header .. "computed maximum operational temperatures %.3fK (H2O) and %.3fK (Na)",
+        log.info(util.sprintf(log_tag .. "computed maximum operational temperatures %.3fK (H2O) and %.3fK (Na)",
                                self.sDB.max_op_temp_H2O, self.sDB.max_op_temp_Na))
     end
 
@@ -289,12 +289,12 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                         _copy_status(pkt.data[7])
                         self.received_status_cache = true
                     else
-                        log.error(log_header .. "RPLC status packet reactor data length mismatch")
+                        log.error(log_tag .. "RPLC status packet reactor data length mismatch")
                     end
                 end
             end
         else
-            log.debug(log_header .. "RPLC status packet invalid")
+            log.debug(log_tag .. "RPLC status packet invalid")
         end
     end
 
@@ -341,7 +341,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
         if pkt.length == 1 then
             return pkt.data[1]
         else
-            log.debug(log_header .. "RPLC ACK length mismatch")
+            log.debug(log_tag .. "RPLC ACK length mismatch")
             return nil
         end
     end
@@ -351,7 +351,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
     local function _handle_packet(pkt)
         -- check sequence number
         if self.r_seq_num ~= pkt.scada_frame.seq_num() then
-            log.warning(log_header .. "sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
+            log.warning(log_tag .. "sequence out-of-order: next = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
             return
         else
             self.r_seq_num = pkt.scada_frame.seq_num() + 1
@@ -362,7 +362,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
             ---@cast pkt rplc_frame
             -- check reactor ID
             if pkt.id ~= reactor_id then
-                log.warning(log_header .. "discarding RPLC packet with ID not matching reactor ID: reactor " .. reactor_id .. " != " .. pkt.id)
+                log.warning(log_tag .. "discarding RPLC packet with ID not matching reactor ID: reactor " .. reactor_id .. " != " .. pkt.id)
                 return
             end
 
@@ -375,7 +375,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                 if pkt.length >= 5 then
                     _handle_status(pkt)
                 else
-                    log.debug(log_header .. "RPLC status packet length mismatch")
+                    log.debug(log_tag .. "RPLC status packet length mismatch")
                 end
             elseif pkt.type == RPLC_TYPE.MEK_STRUCT then
                 -- received reactor structure, record it
@@ -385,7 +385,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                     self.received_struct = true
                     out_queue.push_data(svqtypes.SV_Q_DATA.PLC_BUILD_CHANGED, reactor_id)
                 else
-                    log.debug(log_header .. "RPLC struct packet length mismatch")
+                    log.debug(log_tag .. "RPLC struct packet length mismatch")
                 end
             elseif pkt.type == RPLC_TYPE.MEK_BURN_RATE then
                 -- burn rate acknowledgement
@@ -393,7 +393,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                 if ack then
                     self.acks.burn_rate = true
                 elseif ack == false then
-                    log.debug(log_header .. "burn rate update failed!")
+                    log.debug(log_tag .. "burn rate update failed!")
                 end
 
                 -- send acknowledgement to coordinator
@@ -408,7 +408,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                 if ack then
                     self.sDB.control_state = true
                 elseif ack == false then
-                    log.debug(log_header .. "enable failed!")
+                    log.debug(log_tag .. "enable failed!")
                 end
 
                 -- send acknowledgement to coordinator
@@ -424,7 +424,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                     self.acks.disable = true
                     self.sDB.control_state = false
                 elseif ack == false then
-                    log.debug(log_header .. "disable failed!")
+                    log.debug(log_tag .. "disable failed!")
                 end
             elseif pkt.type == RPLC_TYPE.RPS_SCRAM then
                 -- manual SCRAM acknowledgement
@@ -433,7 +433,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                     self.acks.scram = true
                     self.sDB.control_state = false
                 elseif ack == false then
-                    log.debug(log_header .. "manual SCRAM failed!")
+                    log.debug(log_tag .. "manual SCRAM failed!")
                 end
 
                 -- send acknowledgement to coordinator
@@ -449,7 +449,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                     self.acks.ascram = true
                     self.sDB.control_state = false
                 elseif ack == false then
-                    log.debug(log_header .. " automatic SCRAM failed!")
+                    log.debug(log_tag .. " automatic SCRAM failed!")
                 end
             elseif pkt.type == RPLC_TYPE.RPS_STATUS then
                 -- RPS status packet received, copy data
@@ -459,10 +459,10 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                         -- copied in RPS status data OK
                     else
                         -- error copying RPS status data
-                        log.error(log_header .. "failed to parse RPS status packet data")
+                        log.error(log_tag .. "failed to parse RPS status packet data")
                     end
                 else
-                    log.debug(log_header .. "RPLC RPS status packet length mismatch")
+                    log.debug(log_tag .. "RPLC RPS status packet length mismatch")
                 end
             elseif pkt.type == RPLC_TYPE.RPS_ALARM then
                 -- RPS alarm
@@ -472,10 +472,10 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                         -- copied in RPS status data OK
                     else
                         -- error copying RPS status data
-                        log.error(log_header .. "failed to parse RPS alarm status data")
+                        log.error(log_tag .. "failed to parse RPS alarm status data")
                     end
                 else
-                    log.debug(log_header .. "RPLC RPS alarm packet length mismatch")
+                    log.debug(log_tag .. "RPLC RPS alarm packet length mismatch")
                 end
             elseif pkt.type == RPLC_TYPE.RPS_RESET then
                 -- RPS reset acknowledgement
@@ -485,7 +485,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                     self.sDB.rps_tripped = false
                     self.sDB.rps_trip_cause = "ok"
                 elseif ack == false then
-                    log.debug(log_header .. "RPS reset failed")
+                    log.debug(log_tag .. "RPS reset failed")
                 end
 
                 -- send acknowledgement to coordinator
@@ -498,7 +498,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                 -- RPS auto control reset acknowledgement
                 local ack = _get_ack(pkt)
                 if not ack then
-                    log.debug(log_header .. "RPS auto reset failed")
+                    log.debug(log_tag .. "RPS auto reset failed")
                 end
             elseif pkt.type == RPLC_TYPE.AUTO_BURN_RATE then
                 if pkt.length == 1 then
@@ -506,18 +506,18 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
 
                     if ack == PLC_AUTO_ACK.FAIL then
                         self.acks.burn_rate = false
-                        log.debug(log_header .. "RPLC automatic burn rate set fail")
+                        log.debug(log_tag .. "RPLC automatic burn rate set fail")
                     elseif ack == PLC_AUTO_ACK.DIRECT_SET_OK or ack == PLC_AUTO_ACK.RAMP_SET_OK or ack == PLC_AUTO_ACK.ZERO_DIS_OK then
                         self.acks.burn_rate = true
                     else
                         self.acks.burn_rate = false
-                        log.debug(log_header .. "RPLC automatic burn rate ack unknown")
+                        log.debug(log_tag .. "RPLC automatic burn rate ack unknown")
                     end
                 else
-                    log.debug(log_header .. "RPLC automatic burn rate ack packet length mismatch")
+                    log.debug(log_tag .. "RPLC automatic burn rate ack packet length mismatch")
                 end
             else
-                log.debug(log_header .. "handler received unsupported RPLC packet type " .. pkt.type)
+                log.debug(log_tag .. "handler received unsupported RPLC packet type " .. pkt.type)
             end
         elseif pkt.scada_frame.protocol() == PROTOCOL.SCADA_MGMT then
             ---@cast pkt mgmt_frame
@@ -530,7 +530,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                     self.last_rtt = srv_now - srv_start
 
                     if self.last_rtt > 750 then
-                        log.warning(log_header .. "PLC KEEP_ALIVE round trip time > 750ms (" .. self.last_rtt .. "ms)")
+                        log.warning(log_tag .. "PLC KEEP_ALIVE round trip time > 750ms (" .. self.last_rtt .. "ms)")
                     end
 
                     -- log.debug(log_header .. "PLC RTT = " .. self.last_rtt .. "ms")
@@ -538,13 +538,17 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
 
                     databus.tx_plc_rtt(reactor_id, self.last_rtt)
                 else
-                    log.debug(log_header .. "SCADA keep alive packet length mismatch")
+                    log.debug(log_tag .. "SCADA keep alive packet length mismatch")
                 end
             elseif pkt.type == MGMT_TYPE.CLOSE then
                 -- close the session
                 _close()
+            elseif pkt.type == MGMT_TYPE.ESTABLISH then
+                -- something is wrong, kill the session
+                _close()
+                log.warning(log_tag .. "terminated session due to an unexpected ESTABLISH packet")
             else
-                log.debug(log_header .. "handler received unsupported SCADA_MGMT packet type " .. pkt.type)
+                log.debug(log_tag .. "handler received unsupported SCADA_MGMT packet type " .. pkt.type)
             end
         end
     end
@@ -639,7 +643,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
         _close()
         _send_mgmt(MGMT_TYPE.CLOSE, {})
         println("connection to reactor " .. reactor_id .. " PLC closed by server")
-        log.info(log_header .. "session closed by server")
+        log.info(log_tag .. "session closed by server")
     end
 
     -- iterate the session
@@ -696,7 +700,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                                 _send(RPLC_TYPE.RPS_AUTO_RESET, {})
                             end
                         else
-                            log.error(log_header .. "unsupported command received in in_queue (this is a bug)", true)
+                            log.error(log_tag .. "unsupported command received in in_queue (this is a bug)", true)
                         end
                     elseif message.qtype == mqueue.TYPE.DATA then
                         -- instruction with body
@@ -745,14 +749,14 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
                                 end
                             end
                         else
-                            log.error(log_header .. "unsupported data command received in in_queue (this is a bug)", true)
+                            log.error(log_tag .. "unsupported data command received in in_queue (this is a bug)", true)
                         end
                     end
                 end
 
                 -- max 100ms spent processing queue
                 if util.time() - handle_start > 100 then
-                    log.warning(log_header .. "exceeded 100ms queue process limit")
+                    log.warning(log_tag .. "exceeded 100ms queue process limit")
                     break
                 end
             end
@@ -760,7 +764,7 @@ function plc.new_session(id, s_addr, i_seq_num, reactor_id, in_queue, out_queue,
             -- exit if connection was closed
             if not self.connected then
                 println("connection to reactor " .. reactor_id .. " PLC closed by remote host")
-                log.info(log_header .. "session closed by remote host")
+                log.info(log_tag .. "session closed by remote host")
                 return self.connected
             end
 
diff --git a/supervisor/session/pocket.lua b/supervisor/session/pocket.lua
index 94a4467..fc7098e 100644
--- a/supervisor/session/pocket.lua
+++ b/supervisor/session/pocket.lua
@@ -40,7 +40,7 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
     -- print a log message to the terminal as long as the UI isn't running
     local function println(message) if not fp_ok then util.println_ts(message) end end
 
-    local log_header = "pdg_session(" .. id .. "): "
+    local log_tag = "pdg_session(" .. id .. "): "
 
     local self = {
         -- connection properties
@@ -95,7 +95,7 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
     local function _handle_packet(pkt)
         -- check sequence number
         if self.r_seq_num ~= pkt.scada_frame.seq_num() then
-            log.warning(log_header .. "sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
+            log.warning(log_tag .. "sequence out-of-order: next = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
             return
         else
             self.r_seq_num = pkt.scada_frame.seq_num() + 1
@@ -116,7 +116,7 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
                     self.last_rtt = srv_now - srv_start
 
                     if self.last_rtt > 750 then
-                        log.warning(log_header .. "PDG KEEP_ALIVE round trip time > 750ms (" .. self.last_rtt .. "ms)")
+                        log.warning(log_tag .. "PDG KEEP_ALIVE round trip time > 750ms (" .. self.last_rtt .. "ms)")
                     end
 
                     -- log.debug(log_header .. "PDG RTT = " .. self.last_rtt .. "ms")
@@ -124,11 +124,15 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
 
                     databus.tx_pdg_rtt(id, self.last_rtt)
                 else
-                    log.debug(log_header .. "SCADA keep alive packet length mismatch")
+                    log.debug(log_tag .. "SCADA keep alive packet length mismatch")
                 end
             elseif pkt.type == MGMT_TYPE.CLOSE then
                 -- close the session
                 _close()
+            elseif pkt.type == MGMT_TYPE.ESTABLISH then
+                -- something is wrong, kill the session
+                _close()
+                log.warning(log_tag .. "terminated session due to an unexpected ESTABLISH packet")
             elseif pkt.type == MGMT_TYPE.DIAG_TONE_GET then
                 -- get the state of alarm tones
                 _send_mgmt(MGMT_TYPE.DIAG_TONE_GET, facility.get_alarm_tones())
@@ -145,13 +149,13 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
                             local allow_testing, test_tone_states = facility.diag_set_test_tone(pkt.data[1], pkt.data[2])
                             _send_mgmt(MGMT_TYPE.DIAG_TONE_SET, { allow_testing, test_tone_states })
                         else
-                            log.debug(log_header .. "SCADA diag tone set packet data type mismatch")
+                            log.debug(log_tag .. "SCADA diag tone set packet data type mismatch")
                         end
                     else
-                        log.debug(log_header .. "SCADA diag tone set packet length mismatch")
+                        log.debug(log_tag .. "SCADA diag tone set packet length mismatch")
                     end
                 else
-                    log.debug(log_header .. "DIAG_TONE_SET is blocked without HMAC for security")
+                    log.debug(log_tag .. "DIAG_TONE_SET is blocked without HMAC for security")
                 end
 
                 if not valid then _send_mgmt(MGMT_TYPE.DIAG_TONE_SET, { false }) end
@@ -168,18 +172,18 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
                             local allow_testing, test_alarm_states = facility.diag_set_test_alarm(pkt.data[1], pkt.data[2])
                             _send_mgmt(MGMT_TYPE.DIAG_ALARM_SET, { allow_testing, test_alarm_states })
                         else
-                            log.debug(log_header .. "SCADA diag alarm set packet data type mismatch")
+                            log.debug(log_tag .. "SCADA diag alarm set packet data type mismatch")
                         end
                     else
-                        log.debug(log_header .. "SCADA diag alarm set packet length mismatch")
+                        log.debug(log_tag .. "SCADA diag alarm set packet length mismatch")
                     end
                 else
-                    log.debug(log_header .. "DIAG_ALARM_SET is blocked without HMAC for security")
+                    log.debug(log_tag .. "DIAG_ALARM_SET is blocked without HMAC for security")
                 end
 
                 if not valid then _send_mgmt(MGMT_TYPE.DIAG_ALARM_SET, { false }) end
             else
-                log.debug(log_header .. "handler received unsupported SCADA_MGMT packet type " .. pkt.type)
+                log.debug(log_tag .. "handler received unsupported SCADA_MGMT packet type " .. pkt.type)
             end
         end
     end
@@ -205,7 +209,7 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
         _close()
         _send_mgmt(MGMT_TYPE.CLOSE, {})
         println("connection to pocket diag session " .. id .. " closed by server")
-        log.info(log_header .. "session closed by server")
+        log.info(log_tag .. "session closed by server")
     end
 
     -- iterate the session
@@ -236,7 +240,7 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
 
                 -- max 100ms spent processing queue
                 if util.time() - handle_start > 100 then
-                    log.warning(log_header .. "exceeded 100ms queue process limit")
+                    log.warning(log_tag .. "exceeded 100ms queue process limit")
                     break
                 end
             end
@@ -244,7 +248,7 @@ function pocket.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout,
             -- exit if connection was closed
             if not self.connected then
                 println("connection to pocket diag session " .. id .. " closed by remote host")
-                log.info(log_header .. "session closed by remote host")
+                log.info(log_tag .. "session closed by remote host")
                 return self.connected
             end
 
diff --git a/supervisor/session/rtu.lua b/supervisor/session/rtu.lua
index 2a9a339..7d2494a 100644
--- a/supervisor/session/rtu.lua
+++ b/supervisor/session/rtu.lua
@@ -242,7 +242,7 @@ function rtu.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout, ad
     local function _handle_packet(pkt)
         -- check sequence number
         if self.r_seq_num ~= pkt.scada_frame.seq_num() then
-            log.warning(log_tag .. "sequence out-of-order: last = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
+            log.warning(log_tag .. "sequence out-of-order: next = " .. self.r_seq_num .. ", new = " .. pkt.scada_frame.seq_num())
             return
         else
             self.r_seq_num = pkt.scada_frame.seq_num() + 1
@@ -283,6 +283,10 @@ function rtu.new_session(id, s_addr, i_seq_num, in_queue, out_queue, timeout, ad
             elseif pkt.type == MGMT_TYPE.CLOSE then
                 -- close the session
                 _close()
+            elseif pkt.type == MGMT_TYPE.ESTABLISH then
+                -- something is wrong, kill the session
+                _close()
+                log.warning(log_tag .. "terminated session due to an unexpected ESTABLISH packet")
             elseif pkt.type == MGMT_TYPE.RTU_ADVERT then
                 -- RTU advertisement
                 log.debug(log_tag .. "received updated advertisement")
diff --git a/supervisor/startup.lua b/supervisor/startup.lua
index 9a567ac..a8c0ecb 100644
--- a/supervisor/startup.lua
+++ b/supervisor/startup.lua
@@ -22,7 +22,7 @@ local supervisor = require("supervisor.supervisor")
 
 local svsessions = require("supervisor.session.svsessions")
 
-local SUPERVISOR_VERSION = "v1.5.0"
+local SUPERVISOR_VERSION = "v1.5.1"
 
 local println = util.println
 local println_ts = util.println_ts