diff -up wordpress/wp-admin/includes/admin-filters.php.old wordpress/wp-admin/includes/admin-filters.php
--- wordpress/wp-admin/includes/admin-filters.php.old	2020-01-29 01:45:18.000000000 +0100
+++ wordpress/wp-admin/includes/admin-filters.php	2020-03-25 16:44:02.126665533 +0100
@@ -111,7 +111,6 @@ add_action( 'personal_options_update', '
 add_action( 'load-plugins.php', 'wp_plugin_update_rows', 20 ); // After wp_update_plugins() is called.
 add_action( 'load-themes.php', 'wp_theme_update_rows', 20 ); // After wp_update_themes() is called.
 
-add_action( 'admin_notices', 'update_nag', 3 );
 add_action( 'admin_notices', 'paused_plugins_notice', 5 );
 add_action( 'admin_notices', 'paused_themes_notice', 5 );
 add_action( 'admin_notices', 'maintenance_nag', 10 );
diff -up wordpress/wp-admin/includes/class-core-upgrader.php.old wordpress/wp-admin/includes/class-core-upgrader.php
--- wordpress/wp-admin/includes/class-core-upgrader.php.old	2020-03-25 16:44:02.126665533 +0100
+++ wordpress/wp-admin/includes/class-core-upgrader.php	2020-03-25 16:44:38.649497710 +0100
@@ -270,6 +270,9 @@ class Core_Upgrader extends WP_Upgrader
 	 * @return bool True if we should update to the offered version, otherwise false.
 	 */
 	public static function should_update_to_version( $offered_ver ) {
+		// RPM: nether allow core update
+		return false;
+
 		require ABSPATH . WPINC . '/version.php'; // $wp_version; // x.y.z
 
 		$current_branch = implode( '.', array_slice( preg_split( '/[.-]/', $wp_version ), 0, 2 ) ); // x.y
diff -up wordpress/wp-admin/includes/class-wp-automatic-updater.php.old wordpress/wp-admin/includes/class-wp-automatic-updater.php
--- wordpress/wp-admin/includes/class-wp-automatic-updater.php.old	2020-02-09 17:55:09.000000000 +0100
+++ wordpress/wp-admin/includes/class-wp-automatic-updater.php	2020-03-25 16:44:02.126665533 +0100
@@ -38,7 +38,7 @@ class WP_Automatic_Updater {
 		}
 
 		// More fine grained control can be done through the WP_AUTO_UPDATE_CORE constant and filters.
-		$disabled = defined( 'AUTOMATIC_UPDATER_DISABLED' ) && AUTOMATIC_UPDATER_DISABLED;
+		$disabled = !defined( 'AUTOMATIC_UPDATER_DISABLED' ) || AUTOMATIC_UPDATER_DISABLED;
 
 		/**
 		 * Filters whether to entirely disable background updates.
diff -up wordpress/wp-admin/includes/update.php.old wordpress/wp-admin/includes/update.php
--- wordpress/wp-admin/includes/update.php.old	2020-03-25 16:44:02.127665528 +0100
+++ wordpress/wp-admin/includes/update.php	2020-03-25 16:45:28.396269123 +0100
@@ -338,12 +338,7 @@ function update_right_now_message() {
 		$cur = get_preferred_from_update_core();
 
 		if ( isset( $cur->response ) && 'upgrade' === $cur->response ) {
-			$msg .= sprintf(
-				'<a href="%s" class="button" aria-describedby="wp-version">%s</a> ',
-				network_admin_url( 'update-core.php' ),
-				/* translators: %s: WordPress version number, or 'Latest' string. */
-				sprintf( __( 'Update to %s' ), $cur->current ? $cur->current : __( 'Latest' ) )
-			);
+			$msg .= '';
 		}
 	}
 
diff -up wordpress/wp-includes/load.php.old wordpress/wp-includes/load.php
--- wordpress/wp-includes/load.php.old	2020-02-25 19:33:06.000000000 +0100
+++ wordpress/wp-includes/load.php	2020-03-25 16:44:02.127665528 +0100
@@ -1435,7 +1435,7 @@ function wp_is_file_mod_allowed( $contex
 	 * @param bool   $file_mod_allowed Whether file modifications are allowed.
 	 * @param string $context          The usage context.
 	 */
-	return apply_filters( 'file_mod_allowed', ! defined( 'DISALLOW_FILE_MODS' ) || ! DISALLOW_FILE_MODS, $context );
+	return apply_filters( 'file_mod_allowed', defined( 'DISALLOW_FILE_MODS' ) && ! DISALLOW_FILE_MODS, $context );
 }
 
 /**
diff -up wordpress/wp-includes/update.php.old wordpress/wp-includes/update.php
--- wordpress/wp-includes/update.php.old	2020-02-10 04:30:06.000000000 +0100
+++ wordpress/wp-includes/update.php	2020-03-25 16:44:02.127665528 +0100
@@ -782,10 +782,6 @@ function _maybe_update_themes() {
  * @since 3.1.0
  */
 function wp_schedule_update_checks() {
-	if ( ! wp_next_scheduled( 'wp_version_check' ) && ! wp_installing() ) {
-		wp_schedule_event( time(), 'twicedaily', 'wp_version_check' );
-	}
-
 	if ( ! wp_next_scheduled( 'wp_update_plugins' ) && ! wp_installing() ) {
 		wp_schedule_event( time(), 'twicedaily', 'wp_update_plugins' );
 	}