- strict typing with UM settings;

- wpcs;
- hookdocs;
- added um-deprecated-hooks.php file for leaving the comments about deprecated hooks;
- plugin textdomain native method to register textdomains;

includes/um-deprecated-hooks.php

@@ -0,0 +1,47 @@
+<?php
+/**
+ * Deprecated Ultimate Member hooks.
+ * The place for hookdocs of the Ultimate Member hooks that have been deprecated.
+ */
+
+if ( ! defined( 'ABSPATH' ) ) {
+	exit;
+}
+
+/**
+ * Filters the language locale before loading textdomain.
+ *
+ * @param {string} $language_locale Current language locale.
+ *
+ * @return {string} Maybe changed language locale.
+ *
+ * @since 1.3.x
+ * @depecated 2.8.5 Used WordPress native `load_plugin_textdomain()`. And can be replaced via WordPress native hook 'plugin_locale'.
+ * @hook um_language_locale
+ *
+ * @example <caption>Change UM language locale.</caption>
+ * function my_um_language_locale( $language_locale ) {
+ *     $language_locale = 'es_ES';
+ *     return $language_locale;
+ * }
+ * add_filter( 'um_language_locale', 'my_um_language_locale' );
+ */
+
+/**
+ * Filters the path to the language file (*.mo).
+ *
+ * @param {string} $language_file Default path to the language file.
+ *
+ * @return {string} Language file path.
+ *
+ * @since 1.3.x
+ * @depecated 2.8.5 Used WordPress native `load_plugin_textdomain()`. And can be replaced via WordPress native hook 'load_textdomain_mofile'.
+ * @hook um_language_file
+ *
+ * @example <caption>Change UM language file path.</caption>
+ * function my_um_language_file( $language_file ) {
+ *     $language_file = '{path-to-language-file}';
+ *     return $language_file;
+ * }
+ * add_filter( 'um_language_file', 'my_um_language_file' );
+ */