diff --git a/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h b/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h
index 612c745d..b0d1e206 100644
--- a/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h
+++ b/converter/include/k4SimDelphes/DelphesEDM4HepConverter.h
@@ -5,8 +5,8 @@
 #include "podio/CollectionBase.h"
 
 // edm4hep
-#include "edm4hep/MCParticleConst.h"
-#include "edm4hep/ReconstructedParticle.h"
+#include "edm4hep/MCParticle.h"
+#include "edm4hep/MutableReconstructedParticle.h"
 #include "edm4hep/MCRecoParticleAssociationCollection.h"
 
 // ROOT
@@ -92,7 +92,7 @@ class DelphesEDM4HepConverter {
     fillReferenceCollection<Electron>(delphesCollection, branch, "electron");
   }
 
-edm4hep::MCRecoParticleAssociationCollection* createExternalRecoAssociations(const std::unordered_map<UInt_t, edm4hep::ConstMCParticle>& mc_map);
+edm4hep::MCRecoParticleAssociationCollection* createExternalRecoAssociations(const std::unordered_map<UInt_t, edm4hep::MCParticle>& mc_map);
 
 private:
 
@@ -108,7 +108,7 @@ edm4hep::MCRecoParticleAssociationCollection* createExternalRecoAssociations(con
   // cannot mark DelphesT as const, because for Candidate* the GetCandidates()
   // method is not marked as const.
   template<typename DelphesT>
-  std::optional<edm4hep::ReconstructedParticle> getMatchingReco(/*const*/ DelphesT* delphesCand) const;
+  std::optional<edm4hep::MutableReconstructedParticle> getMatchingReco(/*const*/ DelphesT* delphesCand) const;
 
   using ProcessFunction = void (DelphesEDM4HepConverter::*)(const TClonesArray*, std::string_view const);
 
@@ -123,10 +123,10 @@ edm4hep::MCRecoParticleAssociationCollection* createExternalRecoAssociations(con
   std::string m_mcRecoAssocCollName;
 
   // map from UniqueIDs (delphes generated particles) to MCParticles
-  std::unordered_map<UInt_t, edm4hep::ConstMCParticle> m_genParticleIds;
+  std::unordered_map<UInt_t, edm4hep::MCParticle> m_genParticleIds;
   // map from UniqueIDs (delphes generated particles) to (possibly multiple)
   // ReconstructedParticles
-  std::unordered_multimap<UInt_t, edm4hep::ReconstructedParticle> m_recoParticleGenIds;
+  std::unordered_multimap<UInt_t, edm4hep::MutableReconstructedParticle> m_recoParticleGenIds;
 };
 
 template<typename CollectionT>
diff --git a/converter/include/k4SimDelphes/k4GenParticlesDelphesConverter.h b/converter/include/k4SimDelphes/k4GenParticlesDelphesConverter.h
index f36f1ce6..707c9876 100644
--- a/converter/include/k4SimDelphes/k4GenParticlesDelphesConverter.h
+++ b/converter/include/k4SimDelphes/k4GenParticlesDelphesConverter.h
@@ -64,11 +64,11 @@ class k4GenParticlesDelphesConverter {
     //
   }
 
-  std::unordered_map<UInt_t, edm4hep::ConstMCParticle> getGenParticleIdMap() { return m_genParticleIds;}
+  std::unordered_map<UInt_t, edm4hep::MCParticle> getGenParticleIdMap() { return m_genParticleIds;}
 
 private:
 
-std::unordered_map<UInt_t, edm4hep::ConstMCParticle> m_genParticleIds;
+std::unordered_map<UInt_t, edm4hep::MCParticle> m_genParticleIds;
 
 };
 
diff --git a/converter/src/DelphesEDM4HepConverter.cc b/converter/src/DelphesEDM4HepConverter.cc
index 58391178..d8623a72 100644
--- a/converter/src/DelphesEDM4HepConverter.cc
+++ b/converter/src/DelphesEDM4HepConverter.cc
@@ -49,10 +49,10 @@ template<size_t N>
 void sortBranchesProcessingOrder(std::vector<BranchSettings>& branches,
                                  std::array<std::string_view, N> const& processingOrder);
 
-edm4hep::Track convertTrack(Track const* cand, const double magFieldBz);
+edm4hep::MutableTrack convertTrack(Track const* cand, const double magFieldBz);
 
 void setMotherDaughterRelations(GenParticle const* delphesCand,
-                                edm4hep::MCParticle particle,
+                                edm4hep::MutableMCParticle particle,
                                 edm4hep::MCParticleCollection& mcParticles);
 
 /**
@@ -376,7 +376,7 @@ void DelphesEDM4HepConverter::processScalarHT(const TClonesArray* delphesCollect
 
 
 template<typename DelphesT>
-std::optional<edm4hep::ReconstructedParticle> DelphesEDM4HepConverter::getMatchingReco(DelphesT* delphesCand) const
+std::optional<edm4hep::MutableReconstructedParticle> DelphesEDM4HepConverter::getMatchingReco(DelphesT* delphesCand) const
 {
   // Here we have to do some work to actually match the Delphes candidate to
   // the correct edm4hep::ReconstructedParticle because the possibility exists
@@ -416,7 +416,7 @@ std::optional<edm4hep::ReconstructedParticle> DelphesEDM4HepConverter::getMatchi
   return {};
 }
 
-edm4hep::MCRecoParticleAssociationCollection* DelphesEDM4HepConverter::createExternalRecoAssociations(const std::unordered_map<UInt_t, edm4hep::ConstMCParticle>& mc_map) {
+edm4hep::MCRecoParticleAssociationCollection* DelphesEDM4HepConverter::createExternalRecoAssociations(const std::unordered_map<UInt_t, edm4hep::MCParticle>& mc_map) {
 
   auto mcRecoRelations = new edm4hep::MCRecoParticleAssociationCollection();
     for (const auto& particleID: mc_map) {
@@ -469,9 +469,9 @@ void sortBranchesProcessingOrder(std::vector<BranchSettings>& branches,
 }
 
 
-edm4hep::Track convertTrack(Track const* cand, const double magFieldBz)
+edm4hep::MutableTrack convertTrack(Track const* cand, const double magFieldBz)
 {
-  edm4hep::Track track;
+  edm4hep::MutableTrack track;
   // Delphes does not really provide any information that would go into the
   // track itself. But some information can be used to at least partially
   // populate a TrackState
@@ -535,7 +535,7 @@ edm4hep::Track convertTrack(Track const* cand, const double magFieldBz)
 }
 
 void setMotherDaughterRelations(GenParticle const* delphesCand,
-                                edm4hep::MCParticle particle,
+                                edm4hep::MutableMCParticle particle,
                                 edm4hep::MCParticleCollection& mcParticles)
 {
   // NOTE: it is in general probably not possible to handle all the different
diff --git a/tests/src/compare_delphes_converter_outputs.cpp b/tests/src/compare_delphes_converter_outputs.cpp
index 56fbfb20..f8a8849e 100644
--- a/tests/src/compare_delphes_converter_outputs.cpp
+++ b/tests/src/compare_delphes_converter_outputs.cpp
@@ -62,10 +62,10 @@ void assertSameKinematics(const DelphesT* delphesCand, const EDM4HepT& edm4hepCa
  * Get all MCParticles related to a given ReconstructedParticle
  *
  */
-std::vector<edm4hep::ConstMCParticle>
-getAssociatedMCParticles(edm4hep::ConstReconstructedParticle reco,
+std::vector<edm4hep::MCParticle>
+getAssociatedMCParticles(edm4hep::ReconstructedParticle reco,
                          const edm4hep::MCRecoParticleAssociationCollection& associations) {
-  std::vector<edm4hep::ConstMCParticle> sims;
+  std::vector<edm4hep::MCParticle> sims;
   // NOTE: looping over the whole collection of associations here is super
   // inefficient, but as long as there is no utility for this, implementing the
   // necessary caching is just too much work for this test case here
@@ -102,7 +102,7 @@ std::vector<GenParticle*> getAssociatedMCParticles(const DelphesT* delphesCand)
  */
 template<typename DelphesT>
 bool compareMCRelations(const DelphesT* delphesCand,
-                        edm4hep::ConstReconstructedParticle edm4hepCand,
+                        edm4hep::ReconstructedParticle edm4hepCand,
                         const edm4hep::MCRecoParticleAssociationCollection& associations) {
 
   const auto delphesGenParticles = getAssociatedMCParticles(delphesCand);