diff --git a/doc/src/sgml/ref/pgupgrade.sgml b/doc/src/sgml/ref/pgupgrade.sgml
index d401053edf..8add90e8ed 100644
--- a/doc/src/sgml/ref/pgupgrade.sgml
+++ b/doc/src/sgml/ref/pgupgrade.sgml
@@ -67,7 +67,7 @@ PostgreSQL documentation
  </para>
 
   <para>
-   pg_upgrade supports upgrades from 8.4.X and later to the current
+   pg_upgrade supports upgrades from 9.0.X and later to the current
    major release of <productname>PostgreSQL</productname>, including snapshot and beta releases.
   </para>
  </refsect1>
diff --git a/src/bin/pg_upgrade/check.c b/src/bin/pg_upgrade/check.c
index dc060418e5..26dae5681a 100644
--- a/src/bin/pg_upgrade/check.c
+++ b/src/bin/pg_upgrade/check.c
@@ -316,8 +316,13 @@ check_cluster_versions(void)
 	 * upgrades
 	 */
 
-	if (GET_MAJOR_VERSION(old_cluster.major_version) < 804)
-		pg_fatal("This utility can only upgrade from PostgreSQL version 8.4 and later.\n");
+	/*
+	 * The minimum version supported when this code shipped in a major version
+	 * was 8.4. This has since been raised to 9.0, but the support code for
+	 * dealing with 8.4 remains to avoid refactoring in a backbranch.
+	 */
+	if (GET_MAJOR_VERSION(old_cluster.major_version) < 900)
+		pg_fatal("This utility can only upgrade from PostgreSQL version 9.0 and later.\n");
 
 	/* Only current PG version is supported as a target */
 	if (GET_MAJOR_VERSION(new_cluster.major_version) != GET_MAJOR_VERSION(PG_VERSION_NUM))