diff --git a/ebos/ecltracermodel.hh b/ebos/ecltracermodel.hh
index 0887ac0a8..925ac3cdd 100644
--- a/ebos/ecltracermodel.hh
+++ b/ebos/ecltracermodel.hh
@@ -247,7 +247,7 @@ protected:
             size_t I = elemCtx.globalSpaceIndex(/*dofIdx=*/ 0, /*timIdx=*/0);
             size_t I1 = elemCtx.globalSpaceIndex(/*dofIdx=*/ 0, /*timIdx=*/1);
 
-            Scalar storageOfTimeIndex1[tr.numTracer()];
+            std::vector<Scalar> storageOfTimeIndex1(tr.numTracer());
             if (elemCtx.enableStorageCache()) {
                 for (int tIdx =0; tIdx < tr.numTracer(); ++tIdx) {
                     storageOfTimeIndex1[tIdx] = tr.storageOfTimeIndex1_[tIdx][I];
@@ -302,7 +302,7 @@ protected:
             if (well.getStatus() == Well::Status::SHUT)
                 continue;
 
-            double wtracer[tr.numTracer()];
+            std::vector<double> wtracer(tr.numTracer());
             for (int tIdx =0; tIdx < tr.numTracer(); ++tIdx) {
                 wtracer[tIdx] = well.getTracerProperties().getConcentration(this->tracerNames_[tr.idx_[tIdx]]);
             }
diff --git a/opm/simulators/utils/ParallelRestart.cpp b/opm/simulators/utils/ParallelRestart.cpp
index 6a5f91348..ce65481ba 100644
--- a/opm/simulators/utils/ParallelRestart.cpp
+++ b/opm/simulators/utils/ParallelRestart.cpp
@@ -23,6 +23,7 @@
 
 #include "ParallelRestart.hpp"
 #include <cassert>
+#include <cstdint>
 #include <cstring>
 #include <ctime>
 #include <memory>
@@ -1033,12 +1034,16 @@ template void unpack(std::vector<__VA_ARGS__>& data, \
                      std::vector<char>& buffer, int& position, \
                      Dune::MPIHelper::MPICommunicator comm);
 
+INSTANTIATE_PACK_VECTOR(float)
 INSTANTIATE_PACK_VECTOR(double)
 INSTANTIATE_PACK_VECTOR(std::vector<double>)
 INSTANTIATE_PACK_VECTOR(bool)
 INSTANTIATE_PACK_VECTOR(char)
 INSTANTIATE_PACK_VECTOR(int)
-INSTANTIATE_PACK_VECTOR(size_t)
+INSTANTIATE_PACK_VECTOR(unsigned char)
+INSTANTIATE_PACK_VECTOR(unsigned int)
+INSTANTIATE_PACK_VECTOR(unsigned long int)
+INSTANTIATE_PACK_VECTOR(unsigned long long int)
 INSTANTIATE_PACK_VECTOR(std::time_t)
 INSTANTIATE_PACK_VECTOR(std::array<double, 3>)
 INSTANTIATE_PACK_VECTOR(std::pair<bool,double>)
@@ -1062,14 +1067,17 @@ template void unpack(__VA_ARGS__& data, \
                      std::vector<char>& buffer, int& position, \
                      Dune::MPIHelper::MPICommunicator comm);
 
+INSTANTIATE_PACK(float)
 INSTANTIATE_PACK(double)
-INSTANTIATE_PACK(std::size_t)
 INSTANTIATE_PACK(bool)
 INSTANTIATE_PACK(int)
+INSTANTIATE_PACK(unsigned char)
+INSTANTIATE_PACK(unsigned int)
+INSTANTIATE_PACK(unsigned long int)
+INSTANTIATE_PACK(unsigned long long int)
 INSTANTIATE_PACK(std::array<short,3>)
 INSTANTIATE_PACK(std::array<bool,3>)
 INSTANTIATE_PACK(std::array<int,3>)
-INSTANTIATE_PACK(unsigned char)
 INSTANTIATE_PACK(std::map<std::pair<int,int>,std::pair<bool,double>>)
 INSTANTIATE_PACK(std::optional<double>)
 INSTANTIATE_PACK(std::optional<std::string>)