diff --git a/components/esm/common.hpp b/components/esm/common.hpp
index c0e6151e24..90c60ad6ab 100644
--- a/components/esm/common.hpp
+++ b/components/esm/common.hpp
@@ -25,12 +25,13 @@ namespace ESM
         VER_120 = 0x3f99999a, // TES3
         VER_130 = 0x3fa66666, // TES3
         VER_080 = 0x3f4ccccd, // TES4
-        VER_100 = 0x3f800000, // TES4
+        VER_100 = 0x3f800000, // TES4, FO4
         VER_132 = 0x3fa8f5c3, // FONV Courier's Stash, DeadMoney
         VER_133 = 0x3faa3d71, // FONV HonestHearts
         VER_134 = 0x3fab851f, // FONV, GunRunnersArsenal, LonesomeRoad, OldWorldBlues
         VER_094 = 0x3f70a3d7, // TES5/FO3
-        VER_170 = 0x3fd9999a // TES5
+        VER_170 = 0x3fd9999a, // TES5
+        VER_095 = 0x3f733333, // FO4
     };
 
     // Defines another files (esm or esp) that this file depends upon.
diff --git a/components/esm4/loadnavi.cpp b/components/esm4/loadnavi.cpp
index 09868d258f..5b73af606e 100644
--- a/components/esm4/loadnavi.cpp
+++ b/components/esm4/loadnavi.cpp
@@ -249,9 +249,8 @@ void ESM4::Navigation::load(ESM4::Reader& reader)
             }
             case ESM4::SUB_NVPP:
             {
-                // FIXME: this is both the version for FO4 and for some TES4 files
-                // How to distinguish?
-                if (esmVer == ESM::VER_100)
+                // FIXME: FO4 updates the format
+                if (reader.hasFormVersion() && (esmVer == ESM::VER_095 || esmVer == ESM::VER_100))
                 {
                     reader.skipSubRecordData();
                     break;
diff --git a/components/esm4/loadnavm.cpp b/components/esm4/loadnavm.cpp
index 6298964f28..828fd77ca1 100644
--- a/components/esm4/loadnavm.cpp
+++ b/components/esm4/loadnavm.cpp
@@ -213,7 +213,7 @@ void ESM4::NavMesh::load(ESM4::Reader& reader)
             {
                 // See FIXME in ESM4::Navigation::load.
                 // FO4 updates the format
-                if (esmVer == ESM::VER_100)
+                if (reader.hasFormVersion() && (esmVer == ESM::VER_095 || esmVer == ESM::VER_100))
                 {
                     reader.skipSubRecordData();
                     break;
diff --git a/components/esm4/loadnpc.cpp b/components/esm4/loadnpc.cpp
index 65292e63a8..251af13630 100644
--- a/components/esm4/loadnpc.cpp
+++ b/components/esm4/loadnpc.cpp
@@ -39,7 +39,7 @@ void ESM4::Npc::load(ESM4::Reader& reader)
     mFlags = reader.hdr().record.flags;
 
     std::uint32_t esmVer = reader.esmVersion();
-    mIsTES4 = esmVer == ESM::VER_080 || esmVer == ESM::VER_100;
+    mIsTES4 = (esmVer == ESM::VER_080 || esmVer == ESM::VER_100) && !reader.hasFormVersion();
     mIsFONV = esmVer == ESM::VER_132 || esmVer == ESM::VER_133 || esmVer == ESM::VER_134;
     // mIsTES5 = esmVer == ESM::VER_094 || esmVer == ESM::VER_170; // WARN: FO3 is also VER_094
 
diff --git a/components/esm4/loadrace.cpp b/components/esm4/loadrace.cpp
index 28f91787e6..7434a7f87f 100644
--- a/components/esm4/loadrace.cpp
+++ b/components/esm4/loadrace.cpp
@@ -38,7 +38,7 @@ void ESM4::Race::load(ESM4::Reader& reader)
     mFlags = reader.hdr().record.flags;
 
     std::uint32_t esmVer = reader.esmVersion();
-    bool isTES4 = esmVer == ESM::VER_080 || esmVer == ESM::VER_100;
+    bool isTES4 = (esmVer == ESM::VER_080 || esmVer == ESM::VER_100) && !reader.hasFormVersion();
     bool isFONV = esmVer == ESM::VER_132 || esmVer == ESM::VER_133 || esmVer == ESM::VER_134;
     bool isFO3 = false;
 
diff --git a/components/esm4/reader.cpp b/components/esm4/reader.cpp
index f81a971e15..ce7f534786 100644
--- a/components/esm4/reader.cpp
+++ b/components/esm4/reader.cpp
@@ -201,15 +201,6 @@ namespace ESM4
 
         // restart from the beginning (i.e. "TES4" record header)
         mStream->seekg(0, mStream->beg);
-#if 0
-    unsigned int esmVer = mHeader.mData.version.ui;
-    bool isTes4 = esmVer == ESM::VER_080 || esmVer == ESM::VER_100;
-    //bool isTes5 = esmVer == ESM::VER_094 || esmVer == ESM::VER_170;
-    //bool isFONV = esmVer == ESM::VER_132 || esmVer == ESM::VER_133 || esmVer == ESM::VER_134;
-
-    // TES4 header size is 4 bytes smaller than TES5 header
-    mCtx.recHeaderSize = isTes4 ? sizeof(ESM4::RecordHeader) - 4 : sizeof(ESM4::RecordHeader);
-#endif
         getRecordHeader();
         if (mCtx.recordHeader.record.typeId == REC_TES4)
         {
diff --git a/components/esm4/reader.hpp b/components/esm4/reader.hpp
index a095c23e85..e18c614885 100644
--- a/components/esm4/reader.hpp
+++ b/components/esm4/reader.hpp
@@ -249,6 +249,9 @@ namespace ESM4
         inline unsigned int esmVersion() const { return mHeader.mData.version.ui; }
         inline unsigned int numRecords() const { return mHeader.mData.records; }
 
+        inline bool hasFormVersion() const { return mCtx.recHeaderSize == sizeof(RecordHeader); }
+        inline unsigned int formVersion() const { return mCtx.recordHeader.record.version; }
+
         void buildLStringIndex();
         void getLocalizedString(std::string& str);