diff --git a/src/wp-includes/link-template.php b/src/wp-includes/link-template.php
index da57ebd64df80..f6e20d9b846ca 100644
--- a/src/wp-includes/link-template.php
+++ b/src/wp-includes/link-template.php
@@ -4534,7 +4534,11 @@ function get_avatar_data( $id_or_email, $args = null ) {
 		}
 
 		if ( $email ) {
-			$email_hash = hash( 'sha256', strtolower( trim( $email ) ) );
+			if ( function_exists( 'hash' ) ) {
+				$email_hash = hash( 'sha256', strtolower( trim( $email ) ) );
+			} else {
+				$email_hash = md5( strtolower( trim( $email ) ) );
+			}
 		}
 	}