diff --git a/wp-admin/includes/class-wp-upgrader.php b/wp-admin/includes/class-wp-upgrader.php
index 3cada43ed3..bcf6684ee9 100644
--- a/wp-admin/includes/class-wp-upgrader.php
+++ b/wp-admin/includes/class-wp-upgrader.php
@@ -1649,17 +1649,35 @@ class Theme_Upgrader extends WP_Upgrader {
 			return $source;
 
 		// A proper archive should have a style.css file in the single subdirectory
-		if ( ! file_exists( $working_directory . 'style.css' ) )
-			return new WP_Error( 'incompatible_archive_theme_no_style', $this->strings['incompatible_archive'], __( 'The theme is missing the <code>style.css</code> stylesheet.' ) );
+		if ( ! file_exists( $working_directory . 'style.css' ) ) {
+			return new WP_Error( 'incompatible_archive_theme_no_style', $this->strings['incompatible_archive'],
+				/* translators: %s: style.css */
+				sprintf( __( 'The theme is missing the %s stylesheet.' ),
+					'<code>style.css</code>'
+				)
+			);
+		}
 
 		$info = get_file_data( $working_directory . 'style.css', array( 'Name' => 'Theme Name', 'Template' => 'Template' ) );
 
-		if ( empty( $info['Name'] ) )
-			return new WP_Error( 'incompatible_archive_theme_no_name', $this->strings['incompatible_archive'], __( "The <code>style.css</code> stylesheet doesn't contain a valid theme header." ) );
+		if ( empty( $info['Name'] ) ) {
+			return new WP_Error( 'incompatible_archive_theme_no_name', $this->strings['incompatible_archive'],
+				/* translators: %s: style.css */
+				sprintf( __( 'The %s stylesheet doesn&#8217;t contain a valid theme header.' ),
+					'<code>style.css</code>'
+				)
+			);
+		}
 
 		// If it's not a child theme, it must have at least an index.php to be legit.
-		if ( empty( $info['Template'] ) && ! file_exists( $working_directory . 'index.php' ) )
-			return new WP_Error( 'incompatible_archive_theme_no_index', $this->strings['incompatible_archive'], __( 'The theme is missing the <code>index.php</code> file.' ) );
+		if ( empty( $info['Template'] ) && ! file_exists( $working_directory . 'index.php' ) ) {
+			return new WP_Error( 'incompatible_archive_theme_no_index', $this->strings['incompatible_archive'],
+				/* translators: %s: index.php */
+				sprintf( __( 'The theme is missing the %s file.' ),
+					'<code>index.php</code>'
+				)
+			);
+		}
 
 		return $source;
 	}
@@ -2084,9 +2102,15 @@ class Language_Pack_Upgrader extends WP_Upgrader {
 				$mo = true;
 		}
 
-		if ( ! $mo || ! $po )
+		if ( ! $mo || ! $po ) {
 			return new WP_Error( 'incompatible_archive_pomo', $this->strings['incompatible_archive'],
-				__( 'The language pack is missing either the <code>.po</code> or <code>.mo</code> files.' ) );
+				/* translators: 1: .po 2: .mo */
+				sprintf( __( 'The language pack is missing either the %1$s or %2$s files.' ),
+					'<code>.po</code>',
+					'<code>.mo</code>'
+				)
+			);
+		}
 
 		return $source;
 	}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index d26cadecd1..3992bd60fc 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.4-beta3-35550';
+$wp_version = '4.4-beta3-35551';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.