diff --git a/scripts/base/init-bare.zeek b/scripts/base/init-bare.zeek
index 58eb9ed92c..32ff925f13 100644
--- a/scripts/base/init-bare.zeek
+++ b/scripts/base/init-bare.zeek
@@ -5093,7 +5093,7 @@ export {
 	## The maximum payload size to allocate for the purpose of
 	## payload information in :zeek:see:`mqtt_publish` events (and the
 	## default MQTT logs generated from that).
-	const max_payload_size = 100 &redef;
+	option max_payload_size = 100;
 }
 
 module Cluster;
diff --git a/src/analyzer/protocol/mqtt/CMakeLists.txt b/src/analyzer/protocol/mqtt/CMakeLists.txt
index 11b79d5924..81c8c50b69 100644
--- a/src/analyzer/protocol/mqtt/CMakeLists.txt
+++ b/src/analyzer/protocol/mqtt/CMakeLists.txt
@@ -5,7 +5,7 @@ include_directories(BEFORE ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DI
 
 zeek_plugin_begin(Zeek MQTT)
 zeek_plugin_cc(MQTT.cc Plugin.cc)
-zeek_plugin_bif(types.bif consts.bif events.bif)
+zeek_plugin_bif(types.bif events.bif)
 zeek_plugin_pac(mqtt.pac
                 mqtt-protocol.pac
                 commands/connect.pac
diff --git a/src/analyzer/protocol/mqtt/MQTT.cc b/src/analyzer/protocol/mqtt/MQTT.cc
index 7b4b6bf4ef..5e9fd0ece1 100644
--- a/src/analyzer/protocol/mqtt/MQTT.cc
+++ b/src/analyzer/protocol/mqtt/MQTT.cc
@@ -3,16 +3,25 @@
 #include "plugin/Plugin.h"
 
 #include "MQTT.h"
-#include "analyzer/protocol/tcp/TCP_Reassembler.h"
 #include "Reporter.h"
-#include "events.bif.h"
+#include "mqtt_pac.h"
 
 using namespace analyzer::MQTT;
 
+const ::ID* MQTT_Analyzer::max_payload_size = nullptr;
+
 MQTT_Analyzer::MQTT_Analyzer(Connection* c)
 	: tcp::TCP_ApplicationAnalyzer("MQTT", c)
 	{
 	interp = new binpac::MQTT::MQTT_Conn(this);
+
+	if ( ! max_payload_size )
+		{
+		max_payload_size = global_scope()->Lookup("MQTT::max_payload_size");
+
+		if ( ! max_payload_size )
+			reporter->FatalError("option not defined: 'MQTT::max_payload_size'");
+		}
 	}
 
 MQTT_Analyzer::~MQTT_Analyzer()
diff --git a/src/analyzer/protocol/mqtt/MQTT.h b/src/analyzer/protocol/mqtt/MQTT.h
index 9bd4088241..c12c23790b 100644
--- a/src/analyzer/protocol/mqtt/MQTT.h
+++ b/src/analyzer/protocol/mqtt/MQTT.h
@@ -3,11 +3,10 @@
 #ifndef ANALYZER_PROTOCOL_MQTT_MQTT_H
 #define ANALYZER_PROTOCOL_MQTT_MQTT_H
 
-#include "events.bif.h"
-
 #include "analyzer/protocol/tcp/TCP.h"
+#include "ID.h"
 
-#include "mqtt_pac.h"
+namespace binpac { namespace MQTT { class MQTT_Conn; } }
 
 namespace analyzer { namespace MQTT {
 
@@ -25,6 +24,8 @@ public:
 	static analyzer::Analyzer* InstantiateAnalyzer(Connection* conn)
 		{ return new MQTT_Analyzer(conn); }
 
+	static const ::ID* max_payload_size;
+
 protected:
 	binpac::MQTT::MQTT_Conn* interp;
 
diff --git a/src/analyzer/protocol/mqtt/commands/publish.pac b/src/analyzer/protocol/mqtt/commands/publish.pac
index 4b4661bd80..a7514d60d8 100644
--- a/src/analyzer/protocol/mqtt/commands/publish.pac
+++ b/src/analyzer/protocol/mqtt/commands/publish.pac
@@ -31,9 +31,10 @@ refine flow MQTT_Flow += {
 			                           reinterpret_cast<const char*>(${msg.topic.str}.begin())));
 
 			auto len = ${msg.payload}.length();
+			auto max = analyzer::MQTT::MQTT_Analyzer::max_payload_size->ID_Val()->AsCount();
 
-			if ( len > static_cast<int>(BifConst::MQTT::max_payload_size) )
-				len = BifConst::MQTT::max_payload_size;
+			if ( len > static_cast<int>(max) )
+				len = max;
 
 			m->Assign(4, new StringVal(len,
 			                           reinterpret_cast<const char*>(${msg.payload}.begin())));
diff --git a/src/analyzer/protocol/mqtt/consts.bif b/src/analyzer/protocol/mqtt/consts.bif
deleted file mode 100644
index e61c593dfa..0000000000
--- a/src/analyzer/protocol/mqtt/consts.bif
+++ /dev/null
@@ -1 +0,0 @@
-const MQTT::max_payload_size: count;
diff --git a/src/analyzer/protocol/mqtt/mqtt.pac b/src/analyzer/protocol/mqtt/mqtt.pac
index 2c5438ff1c..376825c541 100644
--- a/src/analyzer/protocol/mqtt/mqtt.pac
+++ b/src/analyzer/protocol/mqtt/mqtt.pac
@@ -4,9 +4,9 @@
 %include bro.pac
 
 %extern{
+	#include "MQTT.h"
 	#include "events.bif.h"
 	#include "types.bif.h"
-	#include "consts.bif.h"
 %}
 
 analyzer MQTT withcontext {
diff --git a/testing/btest/Baseline/coverage.bare-load-baseline/canonified_loaded_scripts.log b/testing/btest/Baseline/coverage.bare-load-baseline/canonified_loaded_scripts.log
index 7405fc6acd..072b83ffe0 100644
--- a/testing/btest/Baseline/coverage.bare-load-baseline/canonified_loaded_scripts.log
+++ b/testing/btest/Baseline/coverage.bare-load-baseline/canonified_loaded_scripts.log
@@ -91,7 +91,6 @@ scripts/base/init-frameworks-and-bifs.zeek
     build/scripts/base/bif/plugins/Zeek_MIME.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_Modbus.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_MQTT.types.bif.zeek
-    build/scripts/base/bif/plugins/Zeek_MQTT.consts.bif.zeek
     build/scripts/base/bif/plugins/Zeek_MQTT.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_MySQL.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_NCP.events.bif.zeek
diff --git a/testing/btest/Baseline/coverage.default-load-baseline/canonified_loaded_scripts.log b/testing/btest/Baseline/coverage.default-load-baseline/canonified_loaded_scripts.log
index 71646dc094..42dbfbd772 100644
--- a/testing/btest/Baseline/coverage.default-load-baseline/canonified_loaded_scripts.log
+++ b/testing/btest/Baseline/coverage.default-load-baseline/canonified_loaded_scripts.log
@@ -91,7 +91,6 @@ scripts/base/init-frameworks-and-bifs.zeek
     build/scripts/base/bif/plugins/Zeek_MIME.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_Modbus.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_MQTT.types.bif.zeek
-    build/scripts/base/bif/plugins/Zeek_MQTT.consts.bif.zeek
     build/scripts/base/bif/plugins/Zeek_MQTT.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_MySQL.events.bif.zeek
     build/scripts/base/bif/plugins/Zeek_NCP.events.bif.zeek
diff --git a/testing/btest/Baseline/plugins.hooks/output b/testing/btest/Baseline/plugins.hooks/output
index 5bd99aabb0..94cb9c0d34 100644
--- a/testing/btest/Baseline/plugins.hooks/output
+++ b/testing/btest/Baseline/plugins.hooks/output
@@ -274,7 +274,7 @@
 0.000000   MetaHookPost  CallFunction(Log::__create_stream, <frame>, (Weird::LOG, [columns=Weird::Info, ev=Weird::log_weird, path=weird])) -> <no result>
 0.000000   MetaHookPost  CallFunction(Log::__create_stream, <frame>, (X509::LOG, [columns=X509::Info, ev=X509::log_x509, path=x509])) -> <no result>
 0.000000   MetaHookPost  CallFunction(Log::__create_stream, <frame>, (mysql::LOG, [columns=MySQL::Info, ev=MySQL::log_mysql, path=mysql])) -> <no result>
-0.000000   MetaHookPost  CallFunction(Log::__write, <frame>, (PacketFilter::LOG, [ts=1565049781.590186, node=zeek, filter=ip or not ip, init=T, success=T])) -> <no result>
+0.000000   MetaHookPost  CallFunction(Log::__write, <frame>, (PacketFilter::LOG, [ts=1565053246.404549, node=zeek, filter=ip or not ip, init=T, success=T])) -> <no result>
 0.000000   MetaHookPost  CallFunction(Log::add_default_filter, <frame>, (Broker::LOG)) -> <no result>
 0.000000   MetaHookPost  CallFunction(Log::add_default_filter, <frame>, (Cluster::LOG)) -> <no result>
 0.000000   MetaHookPost  CallFunction(Log::add_default_filter, <frame>, (Config::LOG)) -> <no result>
@@ -455,7 +455,7 @@
 0.000000   MetaHookPost  CallFunction(Log::create_stream, <frame>, (Weird::LOG, [columns=Weird::Info, ev=Weird::log_weird, path=weird])) -> <no result>
 0.000000   MetaHookPost  CallFunction(Log::create_stream, <frame>, (X509::LOG, [columns=X509::Info, ev=X509::log_x509, path=x509])) -> <no result>
 0.000000   MetaHookPost  CallFunction(Log::create_stream, <frame>, (mysql::LOG, [columns=MySQL::Info, ev=MySQL::log_mysql, path=mysql])) -> <no result>
-0.000000   MetaHookPost  CallFunction(Log::write, <frame>, (PacketFilter::LOG, [ts=1565049781.590186, node=zeek, filter=ip or not ip, init=T, success=T])) -> <no result>
+0.000000   MetaHookPost  CallFunction(Log::write, <frame>, (PacketFilter::LOG, [ts=1565053246.404549, node=zeek, filter=ip or not ip, init=T, success=T])) -> <no result>
 0.000000   MetaHookPost  CallFunction(NetControl::check_plugins, <frame>, ()) -> <no result>
 0.000000   MetaHookPost  CallFunction(NetControl::init, <null>, ()) -> <no result>
 0.000000   MetaHookPost  CallFunction(Notice::want_pp, <frame>, ()) -> <no result>
@@ -491,6 +491,7 @@
 0.000000   MetaHookPost  CallFunction(Option::set_change_handler, <frame>, (Input::default_mode, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)) -> <no result>
 0.000000   MetaHookPost  CallFunction(Option::set_change_handler, <frame>, (Input::default_reader, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)) -> <no result>
 0.000000   MetaHookPost  CallFunction(Option::set_change_handler, <frame>, (KRB::ignored_errors, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)) -> <no result>
+0.000000   MetaHookPost  CallFunction(Option::set_change_handler, <frame>, (MQTT::max_payload_size, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)) -> <no result>
 0.000000   MetaHookPost  CallFunction(Option::set_change_handler, <frame>, (NetControl::default_priority, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)) -> <no result>
 0.000000   MetaHookPost  CallFunction(Option::set_change_handler, <frame>, (Notice::alarmed_types, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)) -> <no result>
 0.000000   MetaHookPost  CallFunction(Option::set_change_handler, <frame>, (Notice::default_suppression_interval, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)) -> <no result>
@@ -606,7 +607,6 @@
 0.000000   MetaHookPost  LoadFile(0, .<...>/Zeek_Login.events.bif.zeek) -> -1
 0.000000   MetaHookPost  LoadFile(0, .<...>/Zeek_Login.functions.bif.zeek) -> -1
 0.000000   MetaHookPost  LoadFile(0, .<...>/Zeek_MIME.events.bif.zeek) -> -1
-0.000000   MetaHookPost  LoadFile(0, .<...>/Zeek_MQTT.consts.bif.zeek) -> -1
 0.000000   MetaHookPost  LoadFile(0, .<...>/Zeek_MQTT.events.bif.zeek) -> -1
 0.000000   MetaHookPost  LoadFile(0, .<...>/Zeek_MQTT.types.bif.zeek) -> -1
 0.000000   MetaHookPost  LoadFile(0, .<...>/Zeek_Modbus.events.bif.zeek) -> -1
@@ -1169,7 +1169,7 @@
 0.000000   MetaHookPre   CallFunction(Log::__create_stream, <frame>, (Weird::LOG, [columns=Weird::Info, ev=Weird::log_weird, path=weird]))
 0.000000   MetaHookPre   CallFunction(Log::__create_stream, <frame>, (X509::LOG, [columns=X509::Info, ev=X509::log_x509, path=x509]))
 0.000000   MetaHookPre   CallFunction(Log::__create_stream, <frame>, (mysql::LOG, [columns=MySQL::Info, ev=MySQL::log_mysql, path=mysql]))
-0.000000   MetaHookPre   CallFunction(Log::__write, <frame>, (PacketFilter::LOG, [ts=1565049781.590186, node=zeek, filter=ip or not ip, init=T, success=T]))
+0.000000   MetaHookPre   CallFunction(Log::__write, <frame>, (PacketFilter::LOG, [ts=1565053246.404549, node=zeek, filter=ip or not ip, init=T, success=T]))
 0.000000   MetaHookPre   CallFunction(Log::add_default_filter, <frame>, (Broker::LOG))
 0.000000   MetaHookPre   CallFunction(Log::add_default_filter, <frame>, (Cluster::LOG))
 0.000000   MetaHookPre   CallFunction(Log::add_default_filter, <frame>, (Config::LOG))
@@ -1350,7 +1350,7 @@
 0.000000   MetaHookPre   CallFunction(Log::create_stream, <frame>, (Weird::LOG, [columns=Weird::Info, ev=Weird::log_weird, path=weird]))
 0.000000   MetaHookPre   CallFunction(Log::create_stream, <frame>, (X509::LOG, [columns=X509::Info, ev=X509::log_x509, path=x509]))
 0.000000   MetaHookPre   CallFunction(Log::create_stream, <frame>, (mysql::LOG, [columns=MySQL::Info, ev=MySQL::log_mysql, path=mysql]))
-0.000000   MetaHookPre   CallFunction(Log::write, <frame>, (PacketFilter::LOG, [ts=1565049781.590186, node=zeek, filter=ip or not ip, init=T, success=T]))
+0.000000   MetaHookPre   CallFunction(Log::write, <frame>, (PacketFilter::LOG, [ts=1565053246.404549, node=zeek, filter=ip or not ip, init=T, success=T]))
 0.000000   MetaHookPre   CallFunction(NetControl::check_plugins, <frame>, ())
 0.000000   MetaHookPre   CallFunction(NetControl::init, <null>, ())
 0.000000   MetaHookPre   CallFunction(Notice::want_pp, <frame>, ())
@@ -1386,6 +1386,7 @@
 0.000000   MetaHookPre   CallFunction(Option::set_change_handler, <frame>, (Input::default_mode, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100))
 0.000000   MetaHookPre   CallFunction(Option::set_change_handler, <frame>, (Input::default_reader, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100))
 0.000000   MetaHookPre   CallFunction(Option::set_change_handler, <frame>, (KRB::ignored_errors, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100))
+0.000000   MetaHookPre   CallFunction(Option::set_change_handler, <frame>, (MQTT::max_payload_size, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100))
 0.000000   MetaHookPre   CallFunction(Option::set_change_handler, <frame>, (NetControl::default_priority, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100))
 0.000000   MetaHookPre   CallFunction(Option::set_change_handler, <frame>, (Notice::alarmed_types, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100))
 0.000000   MetaHookPre   CallFunction(Option::set_change_handler, <frame>, (Notice::default_suppression_interval, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100))
@@ -1501,7 +1502,6 @@
 0.000000   MetaHookPre   LoadFile(0, .<...>/Zeek_Login.events.bif.zeek)
 0.000000   MetaHookPre   LoadFile(0, .<...>/Zeek_Login.functions.bif.zeek)
 0.000000   MetaHookPre   LoadFile(0, .<...>/Zeek_MIME.events.bif.zeek)
-0.000000   MetaHookPre   LoadFile(0, .<...>/Zeek_MQTT.consts.bif.zeek)
 0.000000   MetaHookPre   LoadFile(0, .<...>/Zeek_MQTT.events.bif.zeek)
 0.000000   MetaHookPre   LoadFile(0, .<...>/Zeek_MQTT.types.bif.zeek)
 0.000000   MetaHookPre   LoadFile(0, .<...>/Zeek_Modbus.events.bif.zeek)
@@ -2063,7 +2063,7 @@
 0.000000 | HookCallFunction Log::__create_stream(Weird::LOG, [columns=Weird::Info, ev=Weird::log_weird, path=weird])
 0.000000 | HookCallFunction Log::__create_stream(X509::LOG, [columns=X509::Info, ev=X509::log_x509, path=x509])
 0.000000 | HookCallFunction Log::__create_stream(mysql::LOG, [columns=MySQL::Info, ev=MySQL::log_mysql, path=mysql])
-0.000000 | HookCallFunction Log::__write(PacketFilter::LOG, [ts=1565049781.590186, node=zeek, filter=ip or not ip, init=T, success=T])
+0.000000 | HookCallFunction Log::__write(PacketFilter::LOG, [ts=1565053246.404549, node=zeek, filter=ip or not ip, init=T, success=T])
 0.000000 | HookCallFunction Log::add_default_filter(Broker::LOG)
 0.000000 | HookCallFunction Log::add_default_filter(Cluster::LOG)
 0.000000 | HookCallFunction Log::add_default_filter(Config::LOG)
@@ -2244,7 +2244,7 @@
 0.000000 | HookCallFunction Log::create_stream(Weird::LOG, [columns=Weird::Info, ev=Weird::log_weird, path=weird])
 0.000000 | HookCallFunction Log::create_stream(X509::LOG, [columns=X509::Info, ev=X509::log_x509, path=x509])
 0.000000 | HookCallFunction Log::create_stream(mysql::LOG, [columns=MySQL::Info, ev=MySQL::log_mysql, path=mysql])
-0.000000 | HookCallFunction Log::write(PacketFilter::LOG, [ts=1565049781.590186, node=zeek, filter=ip or not ip, init=T, success=T])
+0.000000 | HookCallFunction Log::write(PacketFilter::LOG, [ts=1565053246.404549, node=zeek, filter=ip or not ip, init=T, success=T])
 0.000000 | HookCallFunction NetControl::check_plugins()
 0.000000 | HookCallFunction NetControl::init()
 0.000000 | HookCallFunction Notice::want_pp()
@@ -2280,6 +2280,7 @@
 0.000000 | HookCallFunction Option::set_change_handler(Input::default_mode, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)
 0.000000 | HookCallFunction Option::set_change_handler(Input::default_reader, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)
 0.000000 | HookCallFunction Option::set_change_handler(KRB::ignored_errors, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)
+0.000000 | HookCallFunction Option::set_change_handler(MQTT::max_payload_size, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)
 0.000000 | HookCallFunction Option::set_change_handler(NetControl::default_priority, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)
 0.000000 | HookCallFunction Option::set_change_handler(Notice::alarmed_types, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)
 0.000000 | HookCallFunction Option::set_change_handler(Notice::default_suppression_interval, Config::config_option_changed{ Config::log = (coerce [$ts=network_time(), $id=Config::ID, $old_value=Config::format_value(lookup_ID(Config::ID)), $new_value=Config::format_value(Config::new_value)] to Config::Info)if ( != Config::location) Config::log$location = Config::locationLog::write(Config::LOG, Config::log)return (Config::new_value)}, -100)
@@ -2395,7 +2396,6 @@
 0.000000 | HookLoadFile  .<...>/Zeek_Login.events.bif.zeek
 0.000000 | HookLoadFile  .<...>/Zeek_Login.functions.bif.zeek
 0.000000 | HookLoadFile  .<...>/Zeek_MIME.events.bif.zeek
-0.000000 | HookLoadFile  .<...>/Zeek_MQTT.consts.bif.zeek
 0.000000 | HookLoadFile  .<...>/Zeek_MQTT.events.bif.zeek
 0.000000 | HookLoadFile  .<...>/Zeek_MQTT.types.bif.zeek
 0.000000 | HookLoadFile  .<...>/Zeek_Modbus.events.bif.zeek
@@ -2678,7 +2678,7 @@
 0.000000 | HookLoadFile  base<...>/xmpp
 0.000000 | HookLoadFile  base<...>/zeek.bif.zeek
 0.000000 | HookLogInit   packet_filter 1/1 {ts (time), node (string), filter (string), init (bool), success (bool)}
-0.000000 | HookLogWrite  packet_filter [ts=1565049781.590186, node=zeek, filter=ip or not ip, init=T, success=T]
+0.000000 | HookLogWrite  packet_filter [ts=1565053246.404549, node=zeek, filter=ip or not ip, init=T, success=T]
 0.000000 | HookQueueEvent NetControl::init()
 0.000000 | HookQueueEvent filter_change_tracking()
 0.000000 | HookQueueEvent zeek_init()
diff --git a/testing/btest/Baseline/scripts.base.protocols.mqtt.mqtt-payload-cap-dynamic/out b/testing/btest/Baseline/scripts.base.protocols.mqtt.mqtt-payload-cap-dynamic/out
new file mode 100644
index 0000000000..94a389c789
--- /dev/null
+++ b/testing/btest/Baseline/scripts.base.protocols.mqtt.mqtt-payload-cap-dynamic/out
@@ -0,0 +1,3 @@
+mqtt_publish, Hello from the Paho blocking client, 35, 35
+mqtt_publish, Hello MQ, 8, 10
+mqtt_publish, Hello, 5, 10
diff --git a/testing/btest/scripts/base/protocols/mqtt/mqtt-payload-cap-dynamic.test b/testing/btest/scripts/base/protocols/mqtt/mqtt-payload-cap-dynamic.test
new file mode 100644
index 0000000000..09dd2cdc91
--- /dev/null
+++ b/testing/btest/scripts/base/protocols/mqtt/mqtt-payload-cap-dynamic.test
@@ -0,0 +1,15 @@
+# @TEST-EXEC: zeek -b -r $TRACES/mqtt.pcap %INPUT > out
+# @TEST-EXEC: btest-diff out
+
+@load policy/protocols/mqtt
+@load base/frameworks/config
+
+event mqtt_publish(c: connection, is_orig: bool, msg_id: count, msg: MQTT::PublishMsg)
+	{
+	print "mqtt_publish", msg$payload, |msg$payload|, msg$payload_len;
+
+	if ( MQTT::max_payload_size > 8 )
+		Config::set_value("MQTT::max_payload_size", 8);
+	else
+		Config::set_value("MQTT::max_payload_size", MQTT::max_payload_size - 3);
+	}