diff --git a/source/blender/blenkernel/BKE_idprop.h b/source/blender/blenkernel/BKE_idprop.h
index 3af5703dcb1..2132cb717da 100644
--- a/source/blender/blenkernel/BKE_idprop.h
+++ b/source/blender/blenkernel/BKE_idprop.h
@@ -86,8 +86,6 @@ struct IDProperty *IDP_NewString(const char *st, const char *name) ATTR_WARN_UNU
  */
 void IDP_AssignStringMaxSize(struct IDProperty *prop, const char *st, int maxncpy) ATTR_NONNULL();
 void IDP_AssignString(struct IDProperty *prop, const char *st) ATTR_NONNULL();
-void IDP_ConcatStringC(struct IDProperty *prop, const char *st) ATTR_NONNULL();
-void IDP_ConcatString(struct IDProperty *str1, struct IDProperty *append) ATTR_NONNULL();
 void IDP_FreeString(struct IDProperty *prop) ATTR_NONNULL();
 
 /*-------- ID Type -------*/
diff --git a/source/blender/blenkernel/intern/idprop.c b/source/blender/blenkernel/intern/idprop.c
index 69c6bd5e0c5..aa0d2db348b 100644
--- a/source/blender/blenkernel/intern/idprop.c
+++ b/source/blender/blenkernel/intern/idprop.c
@@ -416,28 +416,6 @@ void IDP_AssignString(IDProperty *prop, const char *st)
   IDP_AssignStringMaxSize(prop, st, 0);
 }
 
-void IDP_ConcatStringC(IDProperty *prop, const char *st)
-{
-  BLI_assert(prop->type == IDP_STRING);
-
-  int newlen = prop->len + (int)strlen(st);
-  /* We have to remember that prop->len includes the null byte for strings.
-   * so there's no need to add +1 to the resize function. */
-  IDP_ResizeArray(prop, newlen);
-  strcat(prop->data.pointer, st);
-}
-
-void IDP_ConcatString(IDProperty *str1, IDProperty *append)
-{
-  BLI_assert(append->type == IDP_STRING);
-
-  /* Since ->len for strings includes the NULL byte, we have to subtract one or
-   * we'll get an extra null byte after each concatenation operation. */
-  int newlen = str1->len + append->len - 1;
-  IDP_ResizeArray(str1, newlen);
-  strcat(str1->data.pointer, append->data.pointer);
-}
-
 void IDP_FreeString(IDProperty *prop)
 {
   BLI_assert(prop->type == IDP_STRING);