diff --git a/k4Gen/src/components/GenEventFilter.cpp b/k4Gen/src/components/GenEventFilter.cpp
index 0458f56..c0ddc70 100644
--- a/k4Gen/src/components/GenEventFilter.cpp
+++ b/k4Gen/src/components/GenEventFilter.cpp
@@ -16,18 +16,17 @@
 #include "TInterpreter.h"
 #include "TGlobal.h"
 
-DECLARE_COMPONENT(GenEventFilter)
 
 GenEventFilter::GenEventFilter(
     const std::string& name,
-    ISvcLocator* svcLoc) : GaudiAlgorithm(name, svcLoc) {
+    ISvcLocator* svcLoc) : Gaudi::Algorithm(name, svcLoc) {
   declareProperty("particles", m_inColl,
                   "Generated particles to decide on (input)");
 }
 
 StatusCode GenEventFilter::initialize() {
   {
-    StatusCode sc = GaudiAlgorithm::initialize();
+    StatusCode sc = Gaudi::Algorithm::initialize();
     if (sc.isFailure()) {
       return sc;
     }
@@ -141,7 +140,7 @@ StatusCode GenEventFilter::initialize() {
   return StatusCode::SUCCESS;
 }
 
-StatusCode GenEventFilter::execute() {
+StatusCode GenEventFilter::execute(const EventContext& evtCtx) const {
   const edm4hep::MCParticleCollection* inParticles = m_inColl.get();
   m_nEventsSeen++;
 
@@ -180,5 +179,7 @@ StatusCode GenEventFilter::execute() {
 StatusCode GenEventFilter::finalize() {
   debug() << "Number of events seen: " << m_nEventsSeen << endmsg;
 
-  return GaudiAlgorithm::finalize();
+  return Gaudi::Algorithm::finalize();
 }
+
+DECLARE_COMPONENT(GenEventFilter)
diff --git a/k4Gen/src/components/GenEventFilter.h b/k4Gen/src/components/GenEventFilter.h
index a1a4719..7db6e34 100644
--- a/k4Gen/src/components/GenEventFilter.h
+++ b/k4Gen/src/components/GenEventFilter.h
@@ -2,7 +2,7 @@
 #define GENERATION_GENEVENTFILTER_H
 
 // Gaudi
-#include "GaudiAlg/GaudiAlgorithm.h"
+#include "GaudiKernel/Algorithm.h"
 class IProperty;
 class IIncidentSvc;
 class IEventProcessor;
@@ -23,7 +23,7 @@ namespace edm4hep {
  *  @author J. Smiesko
 */
 
-class GenEventFilter : public GaudiAlgorithm {
+class GenEventFilter : public Gaudi::Algorithm {
 
 public:
   /// Constructor
@@ -31,13 +31,13 @@ class GenEventFilter : public GaudiAlgorithm {
   /// Initialize
   virtual StatusCode initialize();
   /// Execute: Applies the filter
-  virtual StatusCode execute();
+  virtual StatusCode execute(const EventContext& evtCtx) const;
   /// Finalize
   virtual StatusCode finalize();
 
 private:
   /// Handle for the MCParticle collection to be read
-  DataHandle<edm4hep::MCParticleCollection> m_inColl{
+  mutable DataHandle<edm4hep::MCParticleCollection> m_inColl{
       "particles", Gaudi::DataHandle::Reader, this};
 
   /// Rule to filter the events with
@@ -49,11 +49,11 @@ class GenEventFilter : public GaudiAlgorithm {
       this, "filterRulePath", "", "Path to the filter rule file"};
 
   /// Targeted number of events.
-  size_t m_nEventsTarget;
+  mutable std::atomic<unsigned int> m_nEventsTarget;
   /// Keep track of how many events were already accepted.
-  size_t m_nEventsAccepted;
+  mutable std::atomic<unsigned int> m_nEventsAccepted;
   /// Keep track of how many events we went through.
-  size_t m_nEventsSeen;
+  mutable std::atomic<unsigned int> m_nEventsSeen;
   /// Pointer to the property.
   SmartIF<IProperty> m_property;
   /// Pointer to the incident service.