diff --git a/definitions/grib2/local/ecmf/section4_extras.def b/definitions/grib2/local/ecmf/section4_extras.def
index 2211aa216..05934e068 100644
--- a/definitions/grib2/local/ecmf/section4_extras.def
+++ b/definitions/grib2/local/ecmf/section4_extras.def
@@ -1,9 +1,12 @@
 # (C) Copyright 2005- ECMWF.
 
-concept modelName ("unknown", "modelNameConcept.def",conceptsDir2,conceptsDir1): no_copy, dump;
+constant modelNameDefault = "unknown";
+constant modelVersionDefault = "unknown";
+
+concept_nofail modelName (modelNameDefault, "modelNameConcept.def",conceptsDir2,conceptsDir1): no_copy, dump;
 
 if (!(modelName is "unknown")) {
-    concept modelVersion ("unknown", "modelVersionConcept_[modelName].def",conceptsDir2,conceptsDir1): no_copy, dump;
+    concept_nofail modelVersion (modelVersionDefault, "modelVersionConcept_[modelName].def",conceptsDir2,conceptsDir1): no_copy, dump;
     alias ls.model = modelName;
     alias mars.model = modelName;
 }
diff --git a/definitions/grib2/localConcepts/era6/modelNameConcept.def b/definitions/grib2/localConcepts/era6/modelNameConcept.def
new file mode 100644
index 000000000..5a7742c41
--- /dev/null
+++ b/definitions/grib2/localConcepts/era6/modelNameConcept.def
@@ -0,0 +1,6 @@
+'IFS' = {
+    backgroundProcess = 255;
+}
+'AIFS' = {
+    backgroundProcess = 1;
+}
diff --git a/definitions/grib2/localConcepts/era6/modelVersionConcept_AIFS.def b/definitions/grib2/localConcepts/era6/modelVersionConcept_AIFS.def
new file mode 100644
index 000000000..b06e75f21
--- /dev/null
+++ b/definitions/grib2/localConcepts/era6/modelVersionConcept_AIFS.def
@@ -0,0 +1,2 @@
+'v1' = { generatingProcessIdentifier = 1; }
+'v2' = { generatingProcessIdentifier = 2; } 
diff --git a/definitions/grib2/localConcepts/era6/modelVersionConcept_IFS.def b/definitions/grib2/localConcepts/era6/modelVersionConcept_IFS.def
new file mode 100644
index 000000000..38757a209
--- /dev/null
+++ b/definitions/grib2/localConcepts/era6/modelVersionConcept_IFS.def
@@ -0,0 +1,2 @@
+'cy48r1' = { generatingProcessIdentifier = 154; }
+'cy47r3' = { generatingProcessIdentifier = 153; }
diff --git a/definitions/grib2/modelNameConcept.def b/definitions/grib2/modelNameConcept.def
new file mode 100644
index 000000000..e69de29bb