diff --git a/wp-admin/includes/ajax-actions.php b/wp-admin/includes/ajax-actions.php
index db22db2924..f11b243e1a 100644
--- a/wp-admin/includes/ajax-actions.php
+++ b/wp-admin/includes/ajax-actions.php
@@ -1443,9 +1443,6 @@ function wp_ajax_add_meta() {
 		if ( '' == trim( $key ) ) {
 			wp_die( __( 'Please provide a custom field name.' ) );
 		}
-		if ( '' == trim( $value ) ) {
-			wp_die( __( 'Please provide a custom field value.' ) );
-		}
 		if ( ! $meta = get_metadata_by_mid( 'post', $mid ) ) {
 			wp_die( 0 ); // if meta doesn't exist
 		}
diff --git a/wp-admin/includes/post.php b/wp-admin/includes/post.php
index 2595f69f7c..adc17ba91f 100644
--- a/wp-admin/includes/post.php
+++ b/wp-admin/includes/post.php
@@ -867,7 +867,7 @@ function add_meta( $post_ID ) {
 		$metavalue = trim( $metavalue );
 	}
 
-	if ( ( '0' === $metavalue || ! empty( $metavalue ) ) && ( ( ( '#NONE#' != $metakeyselect ) && ! empty( $metakeyselect ) ) || ! empty( $metakeyinput ) ) ) {
+	if ( ( ( '#NONE#' != $metakeyselect ) && ! empty( $metakeyselect ) ) || ! empty( $metakeyinput ) ) {
 		/*
 		 * We have a key/value pair. If both the select and the input
 		 * for the key have data, the input takes precedence.
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 89d468abb1..8c27847531 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44152';
+$wp_version = '5.1-alpha-44153';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.