diff --git a/src/Var.cc b/src/Var.cc
index 0fadd1420d..497cda8e60 100644
--- a/src/Var.cc
+++ b/src/Var.cc
@@ -193,7 +193,8 @@ static void make_var(const IDPtr& id, TypePtr t, InitClass c, ExprPtr init,
 		{
 		// This can happen because the grammar allows any "init_class",
 		// including none, to be followed by an expression.
-		init->Warn("initialization not preceded by =/+=/-= is deprecated");
+		// Remove in v6.1 (make an error)
+		init->Warn("Remove in v6.1. Initialization not preceded by =/+=/-= is deprecated.");
 
 		// The historical instances of these, such as the
 		// language/redef-same-prefixtable-idx.zeek btest, treat
diff --git a/testing/btest/Baseline/language.init-mismatch/.stderr b/testing/btest/Baseline/language.init-mismatch/.stderr
index d65bba4b4a..27c9a908dc 100644
--- a/testing/btest/Baseline/language.init-mismatch/.stderr
+++ b/testing/btest/Baseline/language.init-mismatch/.stderr
@@ -1,7 +1,7 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
 error in <...>/init-mismatch.zeek, line 6: invalid constructor list on RHS of assignment (a = 3, 5)
 error in <...>/init-mismatch.zeek, line 6: assignment of non-arithmetic value to arithmetic (count/types) (a = 3, 5)
-warning in <...>/init-mismatch.zeek, line 7: initialization not preceded by =<...>/-= is deprecated (4, 6)
+warning in <...>/init-mismatch.zeek, line 7: Remove in v6.1. Initialization not preceded by =<...>/-= is deprecated. (4, 6)
 error in <...>/init-mismatch.zeek, line 13: different number of indices (list of count,count and list of count,count,count)
 error in <...>/init-mismatch.zeek, line 14: table constructor element lacks '=' structure (bar)
 error in <...>/init-mismatch.zeek, line 17: empty list in untyped initialization ()
diff --git a/testing/btest/Baseline/language.redef-same-prefixtable-idx/.stderr b/testing/btest/Baseline/language.redef-same-prefixtable-idx/.stderr
index 2bf6110ff6..b8c2b8c70e 100644
--- a/testing/btest/Baseline/language.redef-same-prefixtable-idx/.stderr
+++ b/testing/btest/Baseline/language.redef-same-prefixtable-idx/.stderr
@@ -1,3 +1,3 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
-warning in <...>/redef-same-prefixtable-idx.zeek, line 7: initialization not preceded by =<...>/-= is deprecated (3.0.0.0/8 = 1.0.0.0/8)
-warning in <...>/redef-same-prefixtable-idx.zeek, line 8: initialization not preceded by =<...>/-= is deprecated (3.0.0.0/8 = 2.0.0.0/8)
+warning in <...>/redef-same-prefixtable-idx.zeek, line 7: Remove in v6.1. Initialization not preceded by =<...>/-= is deprecated. (3.0.0.0/8 = 1.0.0.0/8)
+warning in <...>/redef-same-prefixtable-idx.zeek, line 8: Remove in v6.1. Initialization not preceded by =<...>/-= is deprecated. (3.0.0.0/8 = 2.0.0.0/8)