diff --git a/libafl/Cargo.toml b/libafl/Cargo.toml
index fea53675ae..e90054d1c9 100644
--- a/libafl/Cargo.toml
+++ b/libafl/Cargo.toml
@@ -34,6 +34,7 @@ gzip = ["miniz_oxide"] # Enables gzip compression in certain parts of the lib
 regex = ["std", "dep:regex"] # enables the NaiveTokenizer and StacktraceObserver
 casr = ["libcasr", "std", "regex"] # enables deduplication based on libcasr for StacktraceObserver
 tcp_manager = ["tokio", "std"] # A simple EventManager proxying everything via TCP
+adaptive_serialization = []
 
 # features hiding dependencies licensed under GPL
 gpl = []
diff --git a/libafl/src/bolts/mod.rs b/libafl/src/bolts/mod.rs
index 78e36cd0b8..6328edb89f 100644
--- a/libafl/src/bolts/mod.rs
+++ b/libafl/src/bolts/mod.rs
@@ -8,7 +8,7 @@ pub mod build_id;
     feature = "std"
 ))]
 pub mod cli;
-#[cfg(feature = "llmp_compression")]
+#[cfg(feature = "gzip")]
 pub mod compress;
 #[cfg(feature = "std")]
 pub mod core_affinity;
diff --git a/libafl/src/events/centralized.rs b/libafl/src/events/centralized.rs
index 6d28d9c3a6..da14c2f0a2 100644
--- a/libafl/src/events/centralized.rs
+++ b/libafl/src/events/centralized.rs
@@ -1,10 +1,14 @@
 //! A wrapper manager to implement a main-secondary architecture with point-to-point channels
 
 use alloc::{boxed::Box, string::String, vec::Vec};
+#[cfg(feature = "adaptive_serialization")]
+use core::time::Duration;
 
 use serde::{Deserialize, Serialize};
 
 use super::{CustomBufEventResult, HasCustomBufHandlers, ProgressReporter};
+#[cfg(feature = "adaptive_serialization")]
+use crate::bolts::current_time;
 use crate::{
     bolts::{
         llmp::{LlmpReceiver, LlmpSender, Tag},
@@ -12,8 +16,8 @@ use crate::{
         ClientId,
     },
     events::{
-        Event, EventConfig, EventFirer, EventManager, EventManagerId, EventProcessor,
-        EventRestarter, HasEventManagerId, LogSeverity,
+        llmp::EventStatsCollector, Event, EventConfig, EventFirer, EventManager, EventManagerId,
+        EventProcessor, EventRestarter, HasEventManagerId, LogSeverity,
     },
     executors::{Executor, HasObservers},
     fuzzer::{EvaluatorObservers, ExecutionProcessor},
@@ -45,9 +49,50 @@ where
     type State = EM::State;
 }
 
+#[cfg(feature = "adaptive_serialization")]
+impl<EM, SP> EventStatsCollector for CentralizedEventManager<EM, SP>
+where
+    EM: EventStatsCollector + UsesState,
+    SP: ShMemProvider,
+{
+    fn serialization_time(&self) -> Duration {
+        self.inner.serialization_time()
+    }
+    fn deserialization_time(&self) -> Duration {
+        self.inner.deserialization_time()
+    }
+    fn serializations_cnt(&self) -> usize {
+        self.inner.serializations_cnt()
+    }
+    fn should_serialize_cnt(&self) -> usize {
+        self.inner.should_serialize_cnt()
+    }
+
+    fn serialization_time_mut(&mut self) -> &mut Duration {
+        self.inner.serialization_time_mut()
+    }
+    fn deserialization_time_mut(&mut self) -> &mut Duration {
+        self.inner.deserialization_time_mut()
+    }
+    fn serializations_cnt_mut(&mut self) -> &mut usize {
+        self.inner.serializations_cnt_mut()
+    }
+    fn should_serialize_cnt_mut(&mut self) -> &mut usize {
+        self.inner.should_serialize_cnt_mut()
+    }
+}
+
+#[cfg(not(feature = "adaptive_serialization"))]
+impl<EM, SP> EventStatsCollector for CentralizedEventManager<EM, SP>
+where
+    EM: EventStatsCollector + UsesState,
+    SP: ShMemProvider,
+{
+}
+
 impl<EM, SP> EventFirer for CentralizedEventManager<EM, SP>
 where
-    EM: EventFirer + HasEventManagerId,
+    EM: EventStatsCollector + EventFirer + HasEventManagerId,
     SP: ShMemProvider,
 {
     fn fire(
@@ -63,9 +108,9 @@ where
                     client_config: _,
                     exit_kind: _,
                     corpus_size: _,
-                    observers_buf: _,
                     time: _,
                     executions: _,
+                    observers_buf: _,
                     forward_id,
                 } => {
                     *forward_id = Some(ClientId(self.inner.mgr_id().0 as u32));
@@ -91,13 +136,55 @@ where
         self.inner.log(state, severity_level, message)
     }
 
-    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Vec<u8>, Error>
+    #[cfg(not(feature = "adaptive_serialization"))]
+    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Option<Vec<u8>>, Error>
     where
         OT: ObserversTuple<Self::State> + Serialize,
     {
         self.inner.serialize_observers(observers)
     }
 
+    #[cfg(feature = "adaptive_serialization")]
+    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Option<Vec<u8>>, Error>
+    where
+        OT: ObserversTuple<Self::State> + Serialize,
+    {
+        const SERIALIZE_TIME_FACTOR: u32 = 4;
+        const SERIALIZE_PERCENTAGE_TRESHOLD: usize = 80;
+
+        let exec_time = observers
+            .match_name::<crate::observers::TimeObserver>("time")
+            .map(|o| o.last_runtime().unwrap_or(Duration::ZERO))
+            .unwrap();
+
+        let mut must_ser = (self.serialization_time() + self.deserialization_time())
+            * SERIALIZE_TIME_FACTOR
+            < exec_time;
+        if must_ser {
+            *self.should_serialize_cnt_mut() += 1;
+        }
+
+        if self.serializations_cnt() > 32 {
+            must_ser = (self.should_serialize_cnt() * 100 / self.serializations_cnt())
+                > SERIALIZE_PERCENTAGE_TRESHOLD;
+        }
+
+        if self.inner.serialization_time() == Duration::ZERO
+            || must_ser
+            || self.serializations_cnt().trailing_zeros() >= 8
+        {
+            let start = current_time();
+            let ser = postcard::to_allocvec(observers)?;
+            *self.inner.serialization_time_mut() = current_time() - start;
+
+            *self.serializations_cnt_mut() += 1;
+            Ok(Some(ser))
+        } else {
+            *self.serializations_cnt_mut() += 1;
+            Ok(None)
+        }
+    }
+
     fn configuration(&self) -> EventConfig {
         self.inner.configuration()
     }
@@ -125,12 +212,13 @@ where
 
 impl<E, EM, SP, Z> EventProcessor<E, Z> for CentralizedEventManager<EM, SP>
 where
-    EM: EventProcessor<E, Z> + EventFirer + HasEventManagerId,
+    EM: EventStatsCollector + EventProcessor<E, Z> + EventFirer + HasEventManagerId,
     SP: ShMemProvider,
     E: HasObservers<State = Self::State> + Executor<Self, Z>,
     for<'a> E::Observers: Deserialize<'a>,
     Z: EvaluatorObservers<E::Observers, State = Self::State>
         + ExecutionProcessor<E::Observers, State = Self::State>,
+    Self::State: HasExecutions + HasMetadata,
 {
     fn process(
         &mut self,
@@ -168,15 +256,36 @@ where
                                 "Received new Testcase to evaluate from secondary node {idx:?}"
                             );
 
-                            // TODO check the config and use the serialized observers
+                            let res = if client_config.match_with(&self.configuration())
+                                && observers_buf.is_some()
+                            {
+                                #[cfg(feature = "adaptive_serialization")]
+                                let start = current_time();
+                                let observers: E::Observers =
+                                    postcard::from_bytes(observers_buf.as_ref().unwrap())?;
 
-                            let res = fuzzer.evaluate_input_with_observers::<E, Self>(
-                                state,
-                                executor,
-                                self,
-                                input.clone(),
-                                false,
-                            )?;
+                                #[cfg(feature = "adaptive_serialization")]
+                                {
+                                    *self.inner.deserialization_time_mut() = current_time() - start;
+                                }
+
+                                fuzzer.process_execution(
+                                    state,
+                                    self,
+                                    input.clone(),
+                                    &observers,
+                                    &exit_kind,
+                                    false,
+                                )?
+                            } else {
+                                fuzzer.evaluate_input_with_observers::<E, Self>(
+                                    state,
+                                    executor,
+                                    self,
+                                    input.clone(),
+                                    false,
+                                )?
+                            };
                             if let Some(item) = res.1 {
                                 log::info!("Added received Testcase as item #{item}");
 
@@ -214,7 +323,7 @@ where
 
 impl<E, EM, SP, Z> EventManager<E, Z> for CentralizedEventManager<EM, SP>
 where
-    EM: EventManager<E, Z>,
+    EM: EventStatsCollector + EventManager<E, Z>,
     EM::State: HasClientPerfMonitor + HasExecutions + HasMetadata,
     SP: ShMemProvider,
     E: HasObservers<State = Self::State> + Executor<Self, Z>,
@@ -242,7 +351,7 @@ where
 
 impl<EM, SP> ProgressReporter for CentralizedEventManager<EM, SP>
 where
-    EM: ProgressReporter + HasEventManagerId,
+    EM: EventStatsCollector + ProgressReporter + HasEventManagerId,
     EM::State: HasClientPerfMonitor + HasMetadata + HasExecutions,
     SP: ShMemProvider,
 {
diff --git a/libafl/src/events/llmp.rs b/libafl/src/events/llmp.rs
index 027306e71f..fa7e71f33f 100644
--- a/libafl/src/events/llmp.rs
+++ b/libafl/src/events/llmp.rs
@@ -11,15 +11,17 @@ use core::{marker::PhantomData, num::NonZeroUsize, time::Duration};
 #[cfg(feature = "std")]
 use std::net::{SocketAddr, ToSocketAddrs};
 
-use serde::Deserialize;
 #[cfg(feature = "std")]
-use serde::{de::DeserializeOwned, Serialize};
+use serde::de::DeserializeOwned;
+use serde::{Deserialize, Serialize};
 #[cfg(feature = "std")]
 use typed_builder::TypedBuilder;
 
 use super::{CustomBufEventResult, CustomBufHandlerFn};
 #[cfg(feature = "std")]
 use crate::bolts::core_affinity::CoreId;
+#[cfg(feature = "adaptive_serialization")]
+use crate::bolts::current_time;
 #[cfg(all(feature = "std", any(windows, not(feature = "fork"))))]
 use crate::bolts::os::startable_self;
 #[cfg(all(unix, feature = "std", not(miri)))]
@@ -49,6 +51,7 @@ use crate::{
     fuzzer::{EvaluatorObservers, ExecutionProcessor},
     inputs::{Input, InputConverter, UsesInput},
     monitors::Monitor,
+    observers::ObserversTuple,
     state::{HasClientPerfMonitor, HasExecutions, HasMetadata, UsesState},
     Error,
 };
@@ -308,6 +311,32 @@ where
     }
 }
 
+/// Collected stats to decide if observers must be serialized or not
+#[cfg(feature = "adaptive_serialization")]
+pub trait EventStatsCollector {
+    /// Expose the collected observers serialization time
+    fn serialization_time(&self) -> Duration;
+    /// Expose the collected observers deserialization time
+    fn deserialization_time(&self) -> Duration;
+    /// How many times observers were serialized
+    fn serializations_cnt(&self) -> usize;
+    /// How many times shoukd have been serialized an observer
+    fn should_serialize_cnt(&self) -> usize;
+
+    /// Expose the collected observers serialization time (mut)
+    fn serialization_time_mut(&mut self) -> &mut Duration;
+    /// Expose the collected observers deserialization time (mut)
+    fn deserialization_time_mut(&mut self) -> &mut Duration;
+    /// How many times observers were serialized (mut)
+    fn serializations_cnt_mut(&mut self) -> &mut usize;
+    /// How many times shoukd have been serialized an observer (mut)
+    fn should_serialize_cnt_mut(&mut self) -> &mut usize;
+}
+
+/// Collected stats to decide if observers must be serialized or not
+#[cfg(not(feature = "adaptive_serialization"))]
+pub trait EventStatsCollector {}
+
 /// An [`EventManager`] that forwards all events to other attached fuzzers on shared maps or via tcp,
 /// using low-level message passing, [`crate::bolts::llmp`].
 pub struct LlmpEventManager<S, SP>
@@ -325,9 +354,50 @@ where
     /// A node will not re-use the observer values sent over LLMP
     /// from nodes with other configurations.
     configuration: EventConfig,
+    #[cfg(feature = "adaptive_serialization")]
+    serialization_time: Duration,
+    #[cfg(feature = "adaptive_serialization")]
+    deserialization_time: Duration,
+    #[cfg(feature = "adaptive_serialization")]
+    serializations_cnt: usize,
+    #[cfg(feature = "adaptive_serialization")]
+    should_serialize_cnt: usize,
     phantom: PhantomData<S>,
 }
 
+#[cfg(feature = "adaptive_serialization")]
+impl<S, SP> EventStatsCollector for LlmpEventManager<S, SP>
+where
+    SP: ShMemProvider + 'static,
+    S: UsesInput,
+{
+    fn serialization_time(&self) -> Duration {
+        self.serialization_time
+    }
+    fn deserialization_time(&self) -> Duration {
+        self.deserialization_time
+    }
+    fn serializations_cnt(&self) -> usize {
+        self.serializations_cnt
+    }
+    fn should_serialize_cnt(&self) -> usize {
+        self.should_serialize_cnt
+    }
+
+    fn serialization_time_mut(&mut self) -> &mut Duration {
+        &mut self.serialization_time
+    }
+    fn deserialization_time_mut(&mut self) -> &mut Duration {
+        &mut self.deserialization_time
+    }
+    fn serializations_cnt_mut(&mut self) -> &mut usize {
+        &mut self.serializations_cnt
+    }
+    fn should_serialize_cnt_mut(&mut self) -> &mut usize {
+        &mut self.should_serialize_cnt
+    }
+}
+
 impl<S, SP> core::fmt::Debug for LlmpEventManager<S, SP>
 where
     SP: ShMemProvider + 'static,
@@ -359,7 +429,7 @@ where
 
 impl<S, SP> LlmpEventManager<S, SP>
 where
-    S: UsesInput + HasExecutions + HasClientPerfMonitor,
+    S: UsesInput,
     SP: ShMemProvider + 'static,
 {
     /// Create a manager from a raw LLMP client
@@ -369,6 +439,14 @@ where
             #[cfg(feature = "llmp_compression")]
             compressor: GzipCompressor::new(COMPRESS_THRESHOLD),
             configuration,
+            #[cfg(feature = "adaptive_serialization")]
+            serialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            deserialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            serializations_cnt: 0,
+            #[cfg(feature = "adaptive_serialization")]
+            should_serialize_cnt: 0,
             phantom: PhantomData,
             custom_buf_handlers: vec![],
         })
@@ -389,6 +467,14 @@ where
             #[cfg(feature = "llmp_compression")]
             compressor: GzipCompressor::new(COMPRESS_THRESHOLD),
             configuration,
+            #[cfg(feature = "adaptive_serialization")]
+            serialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            deserialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            serializations_cnt: 0,
+            #[cfg(feature = "adaptive_serialization")]
+            should_serialize_cnt: 0,
             phantom: PhantomData,
             custom_buf_handlers: vec![],
         })
@@ -407,6 +493,14 @@ where
             #[cfg(feature = "llmp_compression")]
             compressor: GzipCompressor::new(COMPRESS_THRESHOLD),
             configuration,
+            #[cfg(feature = "adaptive_serialization")]
+            serialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            deserialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            serializations_cnt: 0,
+            #[cfg(feature = "adaptive_serialization")]
+            should_serialize_cnt: 0,
             phantom: PhantomData,
             custom_buf_handlers: vec![],
         })
@@ -428,6 +522,14 @@ where
             #[cfg(feature = "llmp_compression")]
             compressor: GzipCompressor::new(COMPRESS_THRESHOLD),
             configuration,
+            #[cfg(feature = "adaptive_serialization")]
+            serialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            deserialization_time: Duration::ZERO,
+            #[cfg(feature = "adaptive_serialization")]
+            serializations_cnt: 0,
+            #[cfg(feature = "adaptive_serialization")]
+            should_serialize_cnt: 0,
             phantom: PhantomData,
             custom_buf_handlers: vec![],
         })
@@ -439,7 +541,13 @@ where
     pub fn to_env(&self, env_name: &str) {
         self.llmp.to_env(env_name).unwrap();
     }
+}
 
+impl<S, SP> LlmpEventManager<S, SP>
+where
+    S: UsesInput + HasExecutions + HasClientPerfMonitor + HasMetadata,
+    SP: ShMemProvider + 'static,
+{
     // Handle arriving events in the client
     #[allow(clippy::unused_self)]
     fn handle_in_client<E, Z>(
@@ -468,18 +576,25 @@ where
             } => {
                 log::info!("Received new Testcase from {client_id:?} ({client_config:?}, forward {forward_id:?})");
 
-                let _res = if client_config.match_with(&self.configuration)
+                let res = if client_config.match_with(&self.configuration)
                     && observers_buf.is_some()
                 {
+                    #[cfg(feature = "adaptive_serialization")]
+                    let start = current_time();
                     let observers: E::Observers =
                         postcard::from_bytes(observers_buf.as_ref().unwrap())?;
+                    #[cfg(feature = "adaptive_serialization")]
+                    {
+                        self.deserialization_time = current_time() - start;
+                    }
+
                     fuzzer.process_execution(state, self, input, &observers, &exit_kind, false)?
                 } else {
                     fuzzer.evaluate_input_with_observers::<E, Self>(
                         state, executor, self, input, false,
                     )?
                 };
-                if let Some(item) = _res.1 {
+                if let Some(item) = res.1 {
                     log::info!("Added received Testcase as item #{item}");
                 }
                 Ok(())
@@ -557,6 +672,55 @@ where
         Ok(())
     }
 
+    #[cfg(not(feature = "adaptive_serialization"))]
+    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Option<Vec<u8>>, Error>
+    where
+        OT: ObserversTuple<Self::State> + Serialize,
+    {
+        Ok(Some(postcard::to_allocvec(observers)?))
+    }
+
+    #[cfg(feature = "adaptive_serialization")]
+    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Option<Vec<u8>>, Error>
+    where
+        OT: ObserversTuple<Self::State> + Serialize,
+    {
+        const SERIALIZE_TIME_FACTOR: u32 = 2;
+        const SERIALIZE_PERCENTAGE_TRESHOLD: usize = 80;
+
+        let exec_time = observers
+            .match_name::<crate::observers::TimeObserver>("time")
+            .map(|o| o.last_runtime().unwrap_or(Duration::ZERO))
+            .unwrap();
+
+        let mut must_ser = (self.serialization_time() + self.deserialization_time())
+            * SERIALIZE_TIME_FACTOR
+            < exec_time;
+        if must_ser {
+            *self.should_serialize_cnt_mut() += 1;
+        }
+
+        if self.serializations_cnt() > 32 {
+            must_ser = (self.should_serialize_cnt() * 100 / self.serializations_cnt())
+                > SERIALIZE_PERCENTAGE_TRESHOLD;
+        }
+
+        if self.serialization_time() == Duration::ZERO
+            || must_ser
+            || self.serializations_cnt().trailing_zeros() >= 8
+        {
+            let start = current_time();
+            let ser = postcard::to_allocvec(observers)?;
+            *self.serialization_time_mut() = current_time() - start;
+
+            *self.serializations_cnt_mut() += 1;
+            Ok(Some(ser))
+        } else {
+            *self.serializations_cnt_mut() += 1;
+            Ok(None)
+        }
+    }
+
     fn configuration(&self) -> EventConfig {
         self.configuration
     }
@@ -577,7 +741,7 @@ where
 
 impl<E, S, SP, Z> EventProcessor<E, Z> for LlmpEventManager<S, SP>
 where
-    S: UsesInput + HasClientPerfMonitor + HasExecutions,
+    S: UsesInput + HasClientPerfMonitor + HasExecutions + HasMetadata,
     SP: ShMemProvider,
     E: HasObservers<State = S> + Executor<Self, Z>,
     for<'a> E::Observers: Deserialize<'a>,
@@ -678,6 +842,47 @@ where
     save_state: bool,
 }
 
+#[cfg(all(feature = "std", feature = "adaptive_serialization"))]
+impl<S, SP> EventStatsCollector for LlmpRestartingEventManager<S, SP>
+where
+    SP: ShMemProvider + 'static,
+    S: UsesInput,
+{
+    fn serialization_time(&self) -> Duration {
+        self.llmp_mgr.serialization_time()
+    }
+    fn deserialization_time(&self) -> Duration {
+        self.llmp_mgr.deserialization_time()
+    }
+    fn serializations_cnt(&self) -> usize {
+        self.llmp_mgr.serializations_cnt()
+    }
+    fn should_serialize_cnt(&self) -> usize {
+        self.llmp_mgr.should_serialize_cnt()
+    }
+
+    fn serialization_time_mut(&mut self) -> &mut Duration {
+        self.llmp_mgr.serialization_time_mut()
+    }
+    fn deserialization_time_mut(&mut self) -> &mut Duration {
+        self.llmp_mgr.deserialization_time_mut()
+    }
+    fn serializations_cnt_mut(&mut self) -> &mut usize {
+        self.llmp_mgr.serializations_cnt_mut()
+    }
+    fn should_serialize_cnt_mut(&mut self) -> &mut usize {
+        self.llmp_mgr.should_serialize_cnt_mut()
+    }
+}
+
+#[cfg(all(feature = "std", not(feature = "adaptive_serialization")))]
+impl<S, SP> EventStatsCollector for LlmpRestartingEventManager<S, SP>
+where
+    SP: ShMemProvider + 'static,
+    S: UsesInput,
+{
+}
+
 #[cfg(feature = "std")]
 impl<S, SP> UsesState for LlmpRestartingEventManager<S, SP>
 where
@@ -711,6 +916,13 @@ where
         self.llmp_mgr.fire(state, event)
     }
 
+    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Option<Vec<u8>>, Error>
+    where
+        OT: ObserversTuple<Self::State> + Serialize,
+    {
+        self.llmp_mgr.serialize_observers(observers)
+    }
+
     fn configuration(&self) -> EventConfig {
         self.llmp_mgr.configuration()
     }
@@ -753,7 +965,7 @@ impl<E, S, SP, Z> EventProcessor<E, Z> for LlmpRestartingEventManager<S, SP>
 where
     E: HasObservers<State = S> + Executor<LlmpEventManager<S, SP>, Z>,
     for<'a> E::Observers: Deserialize<'a>,
-    S: UsesInput + HasExecutions + HasClientPerfMonitor,
+    S: UsesInput + HasExecutions + HasClientPerfMonitor + HasMetadata,
     SP: ShMemProvider + 'static,
     Z: EvaluatorObservers<E::Observers, State = S> + ExecutionProcessor<E::Observers>, //CE: CustomEvent<I>,
 {
diff --git a/libafl/src/events/mod.rs b/libafl/src/events/mod.rs
index 13934f2ef7..5e25a59625 100644
--- a/libafl/src/events/mod.rs
+++ b/libafl/src/events/mod.rs
@@ -435,11 +435,11 @@ pub trait EventFirer: UsesState {
     }
 
     /// Serialize all observers for this type and manager
-    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Vec<u8>, Error>
+    fn serialize_observers<OT>(&mut self, observers: &OT) -> Result<Option<Vec<u8>>, Error>
     where
         OT: ObserversTuple<Self::State> + Serialize,
     {
-        Ok(postcard::to_allocvec(observers)?)
+        Ok(Some(postcard::to_allocvec(observers)?))
     }
 
     /// Get the configuration
@@ -462,46 +462,56 @@ where
         last_report_time: Duration,
         monitor_timeout: Duration,
     ) -> Result<Duration, Error> {
-        let executions = *state.executions();
         let cur = current_time();
         // default to 0 here to avoid crashes on clock skew
         if cur.checked_sub(last_report_time).unwrap_or_default() > monitor_timeout {
-            // Default no introspection implmentation
-            #[cfg(not(feature = "introspection"))]
-            self.fire(
-                state,
-                Event::UpdateExecStats {
-                    executions,
-                    time: cur,
-                    phantom: PhantomData,
-                },
-            )?;
-
-            // If performance monitor are requested, fire the `UpdatePerfMonitor` event
-            #[cfg(feature = "introspection")]
-            {
-                state
-                    .introspection_monitor_mut()
-                    .set_current_time(crate::bolts::cpu::read_time_counter());
-
-                // Send the current monitor over to the manager. This `.clone` shouldn't be
-                // costly as `ClientPerfMonitor` impls `Copy` since it only contains `u64`s
-                self.fire(
-                    state,
-                    Event::UpdatePerfMonitor {
-                        executions,
-                        time: cur,
-                        introspection_monitor: Box::new(state.introspection_monitor().clone()),
-                        phantom: PhantomData,
-                    },
-                )?;
-            }
+            self.report_progress(state)?;
 
             Ok(cur)
         } else {
             Ok(last_report_time)
         }
     }
+
+    /// Send off an info/monitor/heartbeat message to the broker.
+    /// Will return an [`crate::Error`], if the stats could not be sent.
+    fn report_progress(&mut self, state: &mut Self::State) -> Result<(), Error> {
+        let executions = *state.executions();
+        let cur = current_time();
+
+        // Default no introspection implmentation
+        #[cfg(not(feature = "introspection"))]
+        self.fire(
+            state,
+            Event::UpdateExecStats {
+                executions,
+                time: cur,
+                phantom: PhantomData,
+            },
+        )?;
+
+        // If performance monitor are requested, fire the `UpdatePerfMonitor` event
+        #[cfg(feature = "introspection")]
+        {
+            state
+                .introspection_monitor_mut()
+                .set_current_time(crate::bolts::cpu::read_time_counter());
+
+            // Send the current monitor over to the manager. This `.clone` shouldn't be
+            // costly as `ClientPerfMonitor` impls `Copy` since it only contains `u64`s
+            self.fire(
+                state,
+                Event::UpdatePerfMonitor {
+                    executions,
+                    time: cur,
+                    introspection_monitor: Box::new(state.introspection_monitor().clone()),
+                    phantom: PhantomData,
+                },
+            )?;
+        }
+
+        Ok(())
+    }
 }
 
 /// Restartable trait
diff --git a/libafl/src/executors/inprocess.rs b/libafl/src/executors/inprocess.rs
index 559f15a929..e92cc37d13 100644
--- a/libafl/src/executors/inprocess.rs
+++ b/libafl/src/executors/inprocess.rs
@@ -439,6 +439,7 @@ pub(crate) struct InProcessExecutorHandlerData {
     fuzzer_ptr: *mut c_void,
     executor_ptr: *const c_void,
     pub current_input_ptr: *const c_void,
+    pub in_handler: bool,
 
     /// The timeout handler
     #[cfg(any(unix, feature = "std"))]
@@ -504,6 +505,13 @@ impl InProcessExecutorHandlerData {
                 .unwrap()
         }
     }
+
+    #[cfg(any(unix, feature = "std"))]
+    fn set_in_handler(&mut self, v: bool) -> bool {
+        let old = self.in_handler;
+        self.in_handler = v;
+        old
+    }
 }
 
 /// Exception handling needs some nasty unsafe.
@@ -519,6 +527,8 @@ pub(crate) static mut GLOBAL_STATE: InProcessExecutorHandlerData = InProcessExec
     /// The current input for signal handling
     current_input_ptr: ptr::null(),
 
+    in_handler: false,
+
     /// The crash handler fn
     #[cfg(any(unix, feature = "std"))]
     crash_handler: ptr::null(),
@@ -568,6 +578,12 @@ pub fn inprocess_get_input<'a, I>() -> Option<&'a I> {
     unsafe { (GLOBAL_STATE.current_input_ptr as *const I).as_ref() }
 }
 
+/// Know if we ar eexecuting in a crash/timeout handler
+#[must_use]
+pub fn inprocess_in_handler() -> bool {
+    unsafe { GLOBAL_STATE.in_handler }
+}
+
 use crate::{
     corpus::{Corpus, Testcase},
     events::Event,
@@ -716,6 +732,7 @@ mod unix_signal_handler {
         fn handle(&mut self, signal: Signal, info: siginfo_t, context: &mut ucontext_t) {
             unsafe {
                 let data = &mut GLOBAL_STATE;
+                let in_handler = data.set_in_handler(true);
                 match signal {
                     Signal::SigUser2 | Signal::SigAlarm => {
                         if !data.timeout_handler.is_null() {
@@ -730,6 +747,7 @@ mod unix_signal_handler {
                         }
                     }
                 }
+                data.set_in_handler(in_handler);
             }
         }
 
@@ -765,6 +783,7 @@ mod unix_signal_handler {
         panic::set_hook(Box::new(move |panic_info| {
             old_hook(panic_info);
             let data = unsafe { &mut GLOBAL_STATE };
+            let in_handler = data.set_in_handler(true);
             if data.is_valid() {
                 // We are fuzzing!
                 let executor = data.executor_mut::<E>();
@@ -786,6 +805,7 @@ mod unix_signal_handler {
                     libc::_exit(128 + 6);
                 } // SIGABRT exit code
             }
+            data.set_in_handler(in_handler);
         }));
     }
 
@@ -979,6 +999,7 @@ pub mod windows_asan_handler {
             + HasScheduler,
     {
         let data = &mut GLOBAL_STATE;
+        data.set_in_handler(true);
         // Have we set a timer_before?
         if !(data.tp_timer as *mut windows::Win32::System::Threading::TP_TIMER).is_null() {
             /*
@@ -1095,10 +1116,12 @@ mod windows_exception_handler {
         fn handle(&mut self, _code: ExceptionCode, exception_pointers: *mut EXCEPTION_POINTERS) {
             unsafe {
                 let data = &mut GLOBAL_STATE;
+                let in_handler = data.set_in_handler(true);
                 if !data.crash_handler.is_null() {
                     let func: HandlerFuncPtr = transmute(data.crash_handler);
                     (func)(exception_pointers, data);
                 }
+                data.set_in_handler(in_handler);
             }
         }
 
@@ -1125,6 +1148,7 @@ mod windows_exception_handler {
         let old_hook = panic::take_hook();
         panic::set_hook(Box::new(move |panic_info| {
             let data = unsafe { &mut GLOBAL_STATE };
+            let in_handler = data.set_in_handler(true);
             // Have we set a timer_before?
             unsafe {
                 if !(data.tp_timer as *mut windows::Win32::System::Threading::TP_TIMER).is_null() {
@@ -1166,6 +1190,7 @@ mod windows_exception_handler {
                 }
             }
             old_hook(panic_info);
+            data.set_in_handler(in_handler);
         }));
     }
 
diff --git a/libafl/src/executors/timeout.rs b/libafl/src/executors/timeout.rs
index 4c5e6ab75d..bf44fed37c 100644
--- a/libafl/src/executors/timeout.rs
+++ b/libafl/src/executors/timeout.rs
@@ -222,7 +222,7 @@ impl<E> TimeoutExecutor<E> {
         if !self.batch_mode {
             return false;
         }
-        // eprintln!("handle_timeout {:?} {}", self.avg_exec_time, self.avg_mul_k);
+        //eprintln!("handle_timeout {:?} {}", self.avg_exec_time, self.avg_mul_k);
         let cur_time = current_time();
         if !data.is_valid() {
             // outside the target
@@ -490,7 +490,7 @@ where
         if self.batch_mode {
             unsafe {
                 let elapsed = current_time() - self.tmout_start_time;
-                // elapsed may be > than tmout in case of reveived but ingored signal
+                // elapsed may be > than tmout in case of received but ingored signal
                 if elapsed > self.exec_tmout
                     || self.exec_tmout - elapsed < self.avg_exec_time * self.avg_mul_k
                 {
diff --git a/libafl/src/fuzzer/mod.rs b/libafl/src/fuzzer/mod.rs
index e9344df624..84e83ae92f 100644
--- a/libafl/src/fuzzer/mod.rs
+++ b/libafl/src/fuzzer/mod.rs
@@ -225,6 +225,8 @@ where
             last = manager.maybe_report_progress(state, last, monitor_timeout)?;
         }
 
+        manager.report_progress(state)?;
+
         // If we would assume the fuzzer loop will always exit after this, we could do this here:
         // manager.on_restart(state)?;
         // But as the state may grow to a few megabytes,
@@ -397,7 +399,7 @@ where
                     let observers_buf = if manager.configuration() == EventConfig::AlwaysUnique {
                         None
                     } else {
-                        Some(manager.serialize_observers::<OT>(observers)?)
+                        manager.serialize_observers::<OT>(observers)?
                     };
                     manager.fire(
                         state,
@@ -547,7 +549,7 @@ where
         let observers_buf = if manager.configuration() == EventConfig::AlwaysUnique {
             None
         } else {
-            Some(manager.serialize_observers::<OT>(observers)?)
+            manager.serialize_observers::<OT>(observers)?
         };
         manager.fire(
             state,
diff --git a/libafl/src/lib.rs b/libafl/src/lib.rs
index af3c6b1fbd..f41830d0b2 100644
--- a/libafl/src/lib.rs
+++ b/libafl/src/lib.rs
@@ -151,7 +151,7 @@ pub enum Error {
     /// Serialization error
     Serialize(String, ErrorBacktrace),
     /// Compression error
-    #[cfg(feature = "llmp_compression")]
+    #[cfg(feature = "gzip")]
     Compression(ErrorBacktrace),
     /// File related error
     #[cfg(feature = "std")]
@@ -187,7 +187,7 @@ impl Error {
     {
         Error::Serialize(arg.into(), ErrorBacktrace::new())
     }
-    #[cfg(feature = "llmp_compression")]
+    #[cfg(feature = "gzip")]
     /// Compression error
     #[must_use]
     pub fn compression() -> Self {
@@ -285,7 +285,7 @@ impl fmt::Display for Error {
                 write!(f, "Error in Serialization: `{0}`", &s)?;
                 display_error_backtrace(f, b)
             }
-            #[cfg(feature = "llmp_compression")]
+            #[cfg(feature = "gzip")]
             Self::Compression(b) => {
                 write!(f, "Error in decompression")?;
                 display_error_backtrace(f, b)