diff --git a/cgcollector/lib/include/MetaCollector.h b/cgcollector/lib/include/MetaCollector.h
index 6f3a139..ed61b69 100644
--- a/cgcollector/lib/include/MetaCollector.h
+++ b/cgcollector/lib/include/MetaCollector.h
@@ -81,12 +81,20 @@ class FilePropertyCollector : public MetaCollector {
     const auto sourceLocation = decl->getLocation();
     auto& astCtx = decl->getASTContext();
     const auto fullSrcLoc = astCtx.getFullLoc(sourceLocation);
-    const auto fileEntry = fullSrcLoc.getFileEntry();
-    if (!fileEntry) {
-      return result;
+    std::string fileNameStr = "";
+    if (fullSrcLoc.isValid()) {
+#if LLVM_VERSION_MAJOR >= 18
+      const auto fileEntry = fullSrcLoc.getFileEntryRef();
+#else
+      const auto fileEntry = fullSrcLoc.getFileEntry();
+#endif
+      if (!fileEntry) {
+        return result;
+      }
+
+      const auto fileName = fileEntry->getName();
+      fileNameStr = fileName.str();
     }
-    const auto fileName = fileEntry->getName();
-    std::string fileNameStr = fileName.str();
 
     result->isFromSystemInclude = astCtx.getSourceManager().isInSystemHeader(sourceLocation);
 
diff --git a/cgcollector/lib/src/AAUSR.cpp b/cgcollector/lib/src/AAUSR.cpp
index 90099fd..b317069 100644
--- a/cgcollector/lib/src/AAUSR.cpp
+++ b/cgcollector/lib/src/AAUSR.cpp
@@ -42,7 +42,7 @@ bool implementation::printLoc(llvm::raw_ostream& OS, SourceLocation BeginLoc, So
   const auto EndLocOffset = SM.getDecomposedLoc(EndLocExpansion).second;
   const std::pair<FileID, unsigned>& Decomposed = SM.getDecomposedLoc(BeginLocExpansion);
   if (PrintFilename) {
-    const FileEntry* FE = SM.getFileEntryForID(Decomposed.first);
+    auto FE = SM.getFileEntryRefForID(Decomposed.first);
     if (FE) {
       OS << llvm::sys::path::filename(FE->getName());
     } else {
diff --git a/cgcollector/lib/src/AliasAnalysis.cpp b/cgcollector/lib/src/AliasAnalysis.cpp
index 93494d0..b3af019 100644
--- a/cgcollector/lib/src/AliasAnalysis.cpp
+++ b/cgcollector/lib/src/AliasAnalysis.cpp
@@ -822,8 +822,16 @@ bool ASTInformationExtractor::TraverseConstructorInitializer(clang::CXXCtorIniti
   return RecursiveASTVisitor::TraverseConstructorInitializer(CtorInit);
 }
 
+[[nodiscard]] inline bool isUnnamedBitField(clang::FieldDecl* FD) {
+#if LLVM_VERSION_MAJOR < 19
+  return FD->isUnnamedBitfield();
+#else
+  return FD->isUnnamedBitField();
+#endif
+}
+
 bool ASTInformationExtractor::VisitFieldDecl(clang::FieldDecl* FD) {
-  if (FD->isUnnamedBitfield()) {
+  if (isUnnamedBitField(FD)) {
     // Unnamed bitfields can not be referenced
     return true;
   }
diff --git a/cgcollector/lib/src/CallGraph.cpp b/cgcollector/lib/src/CallGraph.cpp
index 19e265e..50cab33 100644
--- a/cgcollector/lib/src/CallGraph.cpp
+++ b/cgcollector/lib/src/CallGraph.cpp
@@ -957,7 +957,9 @@ class CGBuilder : public StmtVisitor<CGBuilder> {
     //    std::cout << "Visiting the lambda expression: " << LEstr.front() << " @ " << LE->getCallOperator() <<
     //    std::endl;
     auto lambdaStaticInvoker = LE->getLambdaClass()->getLambdaStaticInvoker();
-    addCalledDecl(lambdaStaticInvoker, LE->getCallOperator(), nullptr);
+    if (lambdaStaticInvoker) {
+      addCalledDecl(lambdaStaticInvoker, LE->getCallOperator(), nullptr);
+    }
     for (auto conversionIt = LE->getLambdaClass()->conversion_begin();
          conversionIt != LE->getLambdaClass()->conversion_end(); ++conversionIt) {
       if (auto conv = *conversionIt) {
@@ -1165,6 +1167,14 @@ CallGraph::CallGraph() : Root(getOrInsertNode(nullptr)) {}
 
 CallGraph::~CallGraph() = default;
 
+[[nodiscard]] inline bool starts_with(llvm::StringRef Str, llvm::StringRef Prefix) {
+#if LLVM_VERSION_MAJOR < 17
+  return Str.startswith(Prefix);
+#else
+  return Str.starts_with(Prefix);
+#endif
+}
+
 bool CallGraph::includeInGraph(const Decl* D) {
   assert(D);
 
@@ -1184,7 +1194,7 @@ bool CallGraph::includeInGraph(const Decl* D) {
 
     IdentifierInfo* II = FD->getIdentifier();
     // TODO not sure whether we want to include __inline marked functions
-    if (II && II->getName().startswith("__inline")) {
+    if (II && starts_with(II->getName(), "__inline")) {
       return true;
     }
   }
diff --git a/cmake/ClangLLVM.cmake b/cmake/ClangLLVM.cmake
index d19bfd9..36ef085 100644
--- a/cmake/ClangLLVM.cmake
+++ b/cmake/ClangLLVM.cmake
@@ -35,7 +35,8 @@ function(test_llvm_major_version version_string)
   endif()
 
   if(NOT ${valid_version})
-    message(SEND_ERROR "LLVM/Clang version 10, 13, 14, 15, 16, 17, and 18 are supported and tested")
+    message(WARNING "Support for LLVM Version ${version_string} is not tested! Proceed with care.")
+    message(WARNING "LLVM/Clang version 10, 13, 14, 15, 16, 17, 18 are supported and tested")
   endif()
 endfunction()
 
diff --git a/graph/include/CgNode.h b/graph/include/CgNode.h
index dc33c40..0facf55 100644
--- a/graph/include/CgNode.h
+++ b/graph/include/CgNode.h
@@ -106,7 +106,7 @@ class CgNode {
     }
 
     auto nmd = new T(args...);
-    this->template addMetaData(nmd);
+    this->addMetaData(nmd);
     return nmd;
   }
 
diff --git a/graph/include/metadata/MetaData.h b/graph/include/metadata/MetaData.h
index 506f326..ea00ef3 100644
--- a/graph/include/metadata/MetaData.h
+++ b/graph/include/metadata/MetaData.h
@@ -36,8 +36,8 @@ class MetaDataFactory {
   template <class... T>
   static CRTPBase* create(const std::string& s, const nlohmann::json& j) {
     if (data().find(s) == data().end()) {
-      MCGLogger::instance().getErrConsole()->template warn(
-          "Could not create: {}, the Metadata is unknown in you application", s);
+      MCGLogger::instance().getErrConsole()->warn("Could not create: {}, the Metadata is unknown in you application",
+                                                  s);
       return nullptr;
     }
     return data().at(s)(j);
@@ -48,7 +48,7 @@ class MetaDataFactory {
     friend T;
 
     static bool registerT() {
-      MCGLogger::instance().getConsole()->template trace("Registering {} \n", T::key);
+      MCGLogger::instance().getConsole()->trace("Registering {} \n", T::key);
       const auto name = T::key;
       MetaDataFactory::data()[name] = [](const nlohmann::json& j) -> CRTPBase* { return new T(j); };
       return true;
diff --git a/pgis/lib/include/MetaData/CgNodeMetaData.h b/pgis/lib/include/MetaData/CgNodeMetaData.h
index 8d824f8..ad69156 100644
--- a/pgis/lib/include/MetaData/CgNodeMetaData.h
+++ b/pgis/lib/include/MetaData/CgNodeMetaData.h
@@ -240,15 +240,15 @@ class PiraOneData : public metacg::MetaData::Registrar<PiraOneData> {
 template <typename T>
 inline void setPiraOneData(T node, int numStmts = 0, bool hasBody = false, bool dominantRuntime = false,
                           bool inPrevProfile = false) {
- const auto& [has, data] = node->template checkAndGet<PiraOneData>();
- if (has) {
-   data->setNumberOfStatements(numStmts);
-   data->setHasBody(hasBody);
-   data->setDominantRuntime(dominantRuntime);
-   data->setComesFromCube(inPrevProfile);
- } else {
-   assert_pira_one_data();
- }
+  const auto& [has, data] = node->template checkAndGet<PiraOneData>();
+  if (has) {
+    data->setNumberOfStatements(numStmts);
+    data->setHasBody(hasBody);
+    data->setDominantRuntime(dominantRuntime);
+    data->setComesFromCube(inPrevProfile);
+  } else {
+    assert_pira_one_data();
+  }
 }
 
 /**