diff --git a/class-mysql.php b/class-mysql.php
deleted file mode 100644
index c25c183..0000000
--- a/class-mysql.php
+++ /dev/null
@@ -1,115 +0,0 @@
-<?php
-
-/**
- * Connect to DB
- *
- * @since 1.0
- * @return \YOURLS\Database\YDB
- */
-function yourls_db_connect() {
-    global $ydb;
-
-    if ( !defined( 'YOURLS_DB_USER' )
-         or !defined( 'YOURLS_DB_PASS' )
-         or !defined( 'YOURLS_DB_NAME' )
-         or !defined( 'YOURLS_DB_HOST' )
-    ) {
-        yourls_die( yourls__( 'Incorrect DB config, please refer to documentation' ), yourls__( 'Fatal error' ), 503 );
-    }
-
-    $dbhost = YOURLS_DB_HOST;
-    $user = YOURLS_DB_USER;
-    $pass = YOURLS_DB_PASS;
-    $dbname = YOURLS_DB_NAME;
-
-    // This action is deprecated
-    yourls_do_action( 'set_DB_driver', 'deprecated' );
-
-    // Get custom port if any
-    if ( false !== strpos( $dbhost, ':' ) ) {
-        list( $dbhost, $dbport ) = explode( ':', $dbhost );
-        $dbhost = sprintf( '%1$s;port=%2$d', $dbhost, $dbport );
-    }
-
-    $charset = yourls_apply_filter( 'db_connect_charset', 'utf8mb4' );
-
-    /**
-     * Data Source Name (dsn) used to connect the DB
-     *
-     * DSN with PDO is something like:
-     * 'mysql:host=123.4.5.6;dbname=test_db;port=3306'
-     * 'sqlite:/opt/databases/mydb.sq3'
-     * 'pgsql:host=192.168.13.37;port=5432;dbname=omgwtf'
-     */
-    $dsn = sprintf( 'mysql:host=%s;dbname=%s;charset=%s', $dbhost, $dbname, $charset );
-    $dsn = yourls_apply_filter( 'db_connect_custom_dsn', $dsn );
-
-    /**
-     * PDO driver options and attributes
-     *
-     * The PDO constructor is something like:
-     *   new PDO( string $dsn, string $username, string $password [, array $options ] )
-     * The driver options are passed to the PDO constructor, eg array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION)
-     * The attribute options are then set in a foreach($attr as $k=>$v){$db->setAttribute($k, $v)} loop
-     */
-    $driver_options = yourls_apply_filter( 'db_connect_driver_option', [] ); // driver options as key-value pairs
-    $attributes = yourls_apply_filter( 'db_connect_attributes', [] ); // attributes as key-value pairs
-
-    $ydb = new \YOURLS\Database\YDB( $dsn, $user, $pass, $driver_options, $attributes );
-    $ydb->init();
-
-    // Past this point, we're connected
-    yourls_debug_log( sprintf( 'Connected to database %s on %s ', $dbname, $dbhost ) );
-
-    yourls_debug_mode( YOURLS_DEBUG );
-
-    return $ydb;
-}
-
-/**
- * Helper function : return instance of the DB
- *
- * Instead of:
- *     global $ydb;
- *     $ydb->do_stuff()
- * Prefer :
- *     yourls_get_db()->do_stuff()
- *
- * @since  1.7.10
- * @return \YOURLS\Database\YDB
- */
-function yourls_get_db() {
-    // Allow plugins to short-circuit the whole function
-    $pre = yourls_apply_filter( 'shunt_get_db', false );
-    if ( false !== $pre ) {
-        return $pre;
-    }
-
-    global $ydb;
-    $ydb = ( isset( $ydb ) ) ? $ydb : yourls_db_connect();
-    return yourls_apply_filter('get_db', $ydb);
-}
-
-/**
- * Helper function : set instance of DB, or unset it
- *
- * Instead of:
- *     global $ydb;
- *     $ydb = stuff
- * Prefer :
- *     yourls_set_db( stuff )
- * (This is mostly used in the test suite)
- *
- * @since 1.7.10
- * @param  mixed $db    Either a \YOURLS\Database\YDB instance, or anything. If null, the function will unset $ydb
- * @return void
- */
-function yourls_set_db($db) {
-    global $ydb;
-
-    if (is_null($db)) {
-        unset($ydb);
-    } else {
-        $ydb = $db;
-    }
-}