diff --git a/appl/popper/pop_auth.h b/appl/popper/pop_auth.h
index 4d9cd673f..7a900df2f 100644
--- a/appl/popper/pop_auth.h
+++ b/appl/popper/pop_auth.h
@@ -52,9 +52,6 @@ void pop_auth_set_error(const char *message);
 #ifdef KRB5
 extern struct auth_mech gssapi_mech;
 #endif
-#ifdef KRB4
-extern struct auth_mech krb4_mech;
-#endif
 
 
 #endif /* __pop_auth_h__ */
diff --git a/configure.ac b/configure.ac
index 598b599c0..cc3be1575 100644
--- a/configure.ac
+++ b/configure.ac
@@ -196,12 +196,6 @@ DIR_hdbdir="$with_hdbdir"
 AC_SUBST([DIR_hdbdir])
 
 
-dnl no kerberos4 any more
-with_krb4=no
-AC_SUBST(INCLUDE_krb4)
-AC_SUBST(LIB_krb4)
-AM_CONDITIONAL(KRB4, false)
-
 AM_CONDITIONAL(KRB5, true)
 AM_CONDITIONAL(do_roken_rename, true)
 
diff --git a/windows/NTMakefile.config b/windows/NTMakefile.config
index defabfa43..b7b916850 100644
--- a/windows/NTMakefile.config
+++ b/windows/NTMakefile.config
@@ -38,9 +38,6 @@ VER_PRERELEASE=1
 # Enable Kerberos v5 support in applications
 KRB5=1
 
-# Enable Kerberos v4
-# KRB4=1
-
 # Enable PKINIT
 PKINIT=1