diff --git a/src/Var.cc b/src/Var.cc
index d23edc0df8..70540cef48 100644
--- a/src/Var.cc
+++ b/src/Var.cc
@@ -195,18 +195,7 @@ 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.
-		// Remove in v6.1 (make an error)
-		reporter->Deprecation(
-			util::fmt("Remove in v6.1. Initialization not preceded by =/+=/-= is deprecated. (%s)",
-		              obj_desc_short(init.get()).c_str()),
-			init->GetLocationInfo());
-
-		// The historical instances of these, such as the
-		// language/redef-same-prefixtable-idx.zeek btest, treat
-		// this as += rather than =, and with the initializer
-		// implicitly inside a list.
-		init = make_intrusive<ListExpr>(init);
-		c = INIT_EXTRA;
+		init->Error("Initialization not preceded by =/+=/-= is not allowed.");
 		}
 
 	if ( init && init->Tag() == EXPR_LIST )
diff --git a/testing/btest/Baseline/language.init-mismatch/.stderr b/testing/btest/Baseline/language.init-mismatch/.stderr
index 27c9a908dc..294a1efe24 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: Remove in v6.1. Initialization not preceded by =<...>/-= is deprecated. (4, 6)
+error in <...>/init-mismatch.zeek, line 7: Initialization not preceded by =<...>/-= is not allowed. (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 b8c2b8c70e..49d861c74c 100644
--- a/testing/btest/Baseline/language.redef-same-prefixtable-idx/.stderr
+++ b/testing/btest/Baseline/language.redef-same-prefixtable-idx/.stderr
@@ -1,3 +1 @@
 ### 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: 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)
diff --git a/testing/btest/Baseline/language.table-redef/out b/testing/btest/Baseline/language.table-redef/out
index d950ce010e..aed170ff09 100644
--- a/testing/btest/Baseline/language.table-redef/out
+++ b/testing/btest/Baseline/language.table-redef/out
@@ -1,7 +1,7 @@
 ### BTest baseline data generated by btest-diff. Do not edit. Use "btest -U/-u" to update. Requires BTest >= 0.63.
 {
-[abc] = 8.0,
+[abc] = 42.0,
 [neat] = 1.0,
-[cool] = 28.0,
+[cool] = 5.0,
 [def] = 99.0
 }
diff --git a/testing/btest/language/redef-same-prefixtable-idx.zeek b/testing/btest/language/redef-same-prefixtable-idx.zeek
index 838f3fc0ba..194c49746b 100644
--- a/testing/btest/language/redef-same-prefixtable-idx.zeek
+++ b/testing/btest/language/redef-same-prefixtable-idx.zeek
@@ -4,12 +4,8 @@
 
 const my_table: table[subnet] of subnet &redef;
 
-redef my_table[3.0.0.0/8] = 1.0.0.0/8;
-redef my_table[3.0.0.0/8] = 2.0.0.0/8;
-
-# The above is basically a shorthand for:
-# redef my_table += { [3.0.0.0/8] = 1.0.0.0/8 };
-# redef my_table += { [3.0.0.0/8] = 2.0.0.0/8 };
+redef my_table += { [3.0.0.0/8] = 1.0.0.0/8 };
+redef my_table += { [3.0.0.0/8] = 2.0.0.0/8 };
 
 event zeek_init()
 	{
diff --git a/testing/btest/language/table-redef.zeek b/testing/btest/language/table-redef.zeek
index 51c4360044..87a12580b2 100644
--- a/testing/btest/language/table-redef.zeek
+++ b/testing/btest/language/table-redef.zeek
@@ -18,9 +18,7 @@ redef foo -= { ["ghi"] = 0.0 };
 # RHS can be a table value
 redef foo += table(["cool"] = 5.0, ["neat"] = 1.0);
 
-# Redef at a single index is allowed, same as += when RHS has overlapping index
-redef foo["cool"] = 28.0;
-redef foo["abc"] = 8.0;
+# redef a single element using +=
 redef foo += { ["def"] = 99.0 };
 
 print foo;