diff --git a/functions-upgrade.php b/functions-upgrade.php
deleted file mode 100644
index 4b48145..0000000
--- a/functions-upgrade.php
+++ /dev/null
@@ -1,453 +0,0 @@
-<?php
-
-/**
- * Upgrade YOURLS and DB schema
- *
- * Note to devs : prefer update function names using the SQL version, eg yourls_update_to_506(),
- * rather than using the YOURLS version number, eg yourls_update_to_18(). This is to allow having
- * multiple SQL update during the dev cycle of the same Y0URLS version
- *
- * @param string|int $step
- * @param string $oldver
- * @param string $newver
- * @param string|int $oldsql
- * @param string|int $newsql
- * @return void
- */
-function yourls_upgrade($step, $oldver, $newver, $oldsql, $newsql ) {
-
-    /**
-     *  Sanitize input. Two notes :
-     *  - they should already be sanitized in the caller, eg admin/upgrade.php
-     *    (but hey, let's make sure)
-     *  - some vars may not be used at the moment
-     *    (and this is ok, they are here in case a future upgrade procedure needs them)
-     */
-    $step   = intval($step);
-    $oldsql = intval($oldsql);
-    $newsql = intval($newsql);
-    $oldver = yourls_sanitize_version($oldver);
-    $newver = yourls_sanitize_version($newver);
-
-    yourls_maintenance_mode(true);
-
-    // special case for 1.3: the upgrade is a multi step procedure
-	if( $oldsql == 100 ) {
-		yourls_upgrade_to_14( $step );
-	}
-
-	// other upgrades which are done in a single pass
-	switch( $step ) {
-
-	case 1:
-	case 2:
-		if( $oldsql < 210 )
-			yourls_upgrade_to_141();
-
-		if( $oldsql < 220 )
-			yourls_upgrade_to_143();
-
-		if( $oldsql < 250 )
-			yourls_upgrade_to_15();
-
-		if( $oldsql < 482 )
-			yourls_upgrade_482(); // that was somewhere 1.5 and 1.5.1 ...
-
-		if( $oldsql < 506 ) {
-            /**
-             * 505 was the botched update with the wrong collation, see #2766
-             * 506 is the updated collation.
-             * We want :
-             *      people on 505 to update to 506
-             *      people before 505 to update to the FIXED complete upgrade
-             */
-			if( $oldsql == 505 ) {
-                yourls_upgrade_505_to_506();
-            } else {
-                yourls_upgrade_to_506();
-            }
-        }
-
-		yourls_redirect_javascript( yourls_admin_url( "upgrade.php?step=3" ) );
-
-		break;
-
-	case 3:
-		// Update options to reflect latest version
-		yourls_update_option( 'version', YOURLS_VERSION );
-		yourls_update_option( 'db_version', YOURLS_DB_VERSION );
-        yourls_maintenance_mode(false);
-		break;
-	}
-}
-
-/************************** 1.6 -> 1.8 **************************/
-
-/**
- * Update to 506, just the fix for people who had updated to master on 1.7.10
- *
- */
-function yourls_upgrade_505_to_506() {
-    echo "<p>Updating DB. Please wait...</p>";
-	// Fix collation which was wrongly set at first to utf8mb4_unicode_ci
-	$query = sprintf('ALTER TABLE `%s` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_bin;', YOURLS_DB_TABLE_URL);
-
-    try {
-        yourls_get_db()->perform($query);
-    } catch (\Exception $e) {
-        echo "<p class='error'>Unable to update the DB.</p>";
-        echo "<p>Could not change collation. You will have to fix things manually :(. The error was
-        <pre>";
-        echo $e->getMessage();
-        echo "/n</pre>";
-        die();
-    }
-
-    echo "<p class='success'>OK!</p>";
-}
-
-/**
- * Update to 506
- *
- */
-function yourls_upgrade_to_506() {
-    $ydb = yourls_get_db();
-    $error_msg = [];
-
-    echo "<p>Updating DB. Please wait...</p>";
-
-    $queries = array(
-        'database charset'     => sprintf('ALTER DATABASE `%s` CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci;', YOURLS_DB_NAME),
-        'options charset'      => sprintf('ALTER TABLE `%s` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;', YOURLS_DB_TABLE_OPTIONS),
-        'short URL varchar'    => sprintf("ALTER TABLE `%s` CHANGE `keyword` `keyword` VARCHAR(100) CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL DEFAULT '';", YOURLS_DB_TABLE_URL),
-        'short URL type url'   => sprintf("ALTER TABLE `%s` CHANGE `url` `url` TEXT CHARACTER SET utf8mb4 COLLATE utf8mb4_bin NOT NULL;", YOURLS_DB_TABLE_URL),
-        'short URL type title' => sprintf("ALTER TABLE `%s` CHANGE `title` `title` TEXT CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci", YOURLS_DB_TABLE_URL),
-        'short URL charset'    => sprintf('ALTER TABLE `%s` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_bin;', YOURLS_DB_TABLE_URL),
-    );
-
-    foreach($queries as $what => $query) {
-        try {
-            $ydb->perform($query);
-        } catch (\Exception $e) {
-            $error_msg[] = $e->getMessage();
-        }
-    }
-
-    if( $error_msg ) {
-        echo "<p class='error'>Unable to update the DB.</p>";
-        echo "<p>You will have to manually fix things, sorry for the inconvenience :(</p>";
-        echo "<p>The errors were:
-        <pre>";
-        foreach( $error_msg as $error ) {
-            echo "$error\n";
-        }
-        echo "</pre>";
-        die();
-    }
-
-    echo "<p class='success'>OK!</p>";
-}
-
-/************************** 1.5 -> 1.6 **************************/
-
-/**
- * Upgrade r482
- *
- */
-function yourls_upgrade_482() {
-	// Change URL title charset to UTF8
-	$table_url = YOURLS_DB_TABLE_URL;
-	$sql = "ALTER TABLE `$table_url` CHANGE `title` `title` TEXT CHARACTER SET utf8;";
-	yourls_get_db()->perform( $sql );
-	echo "<p>Updating table structure. Please wait...</p>";
-}
-
-/************************** 1.4.3 -> 1.5 **************************/
-
-/**
- * Main func for upgrade from 1.4.3 to 1.5
- *
- */
-function yourls_upgrade_to_15( ) {
-	// Create empty 'active_plugins' entry in the option if needed
-	if( yourls_get_option( 'active_plugins' ) === false )
-		yourls_add_option( 'active_plugins', array() );
-	echo "<p>Enabling the plugin API. Please wait...</p>";
-
-	// Alter URL table to store titles
-	$table_url = YOURLS_DB_TABLE_URL;
-	$sql = "ALTER TABLE `$table_url` ADD `title` TEXT AFTER `url`;";
-	yourls_get_db()->perform( $sql );
-	echo "<p>Updating table structure. Please wait...</p>";
-
-	// Update .htaccess
-	yourls_create_htaccess();
-	echo "<p>Updating .htaccess file. Please wait...</p>";
-}
-
-/************************** 1.4.1 -> 1.4.3 **************************/
-
-/**
- * Main func for upgrade from 1.4.1 to 1.4.3
- *
- */
-function yourls_upgrade_to_143( ) {
-	// Check if we have 'keyword' (borked install) or 'shorturl' (ok install)
-	$ydb = yourls_get_db();
-	$table_log = YOURLS_DB_TABLE_LOG;
-	$sql = "SHOW COLUMNS FROM `$table_log`";
-	$cols = $ydb->fetchObjects( $sql );
-	if ( $cols[2]->Field == 'keyword' ) {
-		$sql = "ALTER TABLE `$table_log` CHANGE `keyword` `shorturl` VARCHAR( 200 ) BINARY;";
-		$ydb->query( $sql );
-	}
-	echo "<p>Structure of existing tables updated. Please wait...</p>";
-}
-
-/************************** 1.4 -> 1.4.1 **************************/
-
-/**
- * Main func for upgrade from 1.4 to 1.4.1
- *
- */
-function yourls_upgrade_to_141( ) {
-	// Kill old cookies from 1.3 and prior
-	setcookie('yourls_username', '', time() - 3600 );
-	setcookie('yourls_password', '', time() - 3600 );
-	// alter table URL
-	yourls_alter_url_table_to_141();
-	// recreate the htaccess file if needed
-	yourls_create_htaccess();
-}
-
-/**
- * Alter table URL to 1.4.1
- *
- */
-function yourls_alter_url_table_to_141() {
-	$table_url = YOURLS_DB_TABLE_URL;
-	$alter = "ALTER TABLE `$table_url` CHANGE `keyword` `keyword` VARCHAR( 200 ) BINARY, CHANGE `url` `url` TEXT BINARY ";
-	yourls_get_db()->perform( $alter );
-	echo "<p>Structure of existing tables updated. Please wait...</p>";
-}
-
-
-/************************** 1.3 -> 1.4 **************************/
-
-/**
- * Main func for upgrade from 1.3-RC1 to 1.4
- *
- */
-function yourls_upgrade_to_14( $step ) {
-
-	switch( $step ) {
-	case 1:
-		// create table log & table options
-		// update table url structure
-		// update .htaccess
-		yourls_create_tables_for_14(); // no value returned, assuming it went OK
-		yourls_alter_url_table_to_14(); // no value returned, assuming it went OK
-		$clean = yourls_clean_htaccess_for_14(); // returns bool
-		$create = yourls_create_htaccess(); // returns bool
-		if ( !$create )
-			echo "<p class='warning'>Please create your <tt>.htaccess</tt> file (I could not do it for you). Please refer to <a href='http://yourls.org/htaccess'>http://yourls.org/htaccess</a>.";
-		yourls_redirect_javascript( yourls_admin_url( "upgrade.php?step=2&oldver=1.3&newver=1.4&oldsql=100&newsql=200" ), $create );
-		break;
-
-	case 2:
-		// convert each link in table url
-		yourls_update_table_to_14();
-		break;
-
-	case 3:
-		// update table url structure part 2: recreate indexes
-		yourls_alter_url_table_to_14_part_two();
-		// update version & db_version & next_id in the option table
-		// attempt to drop YOURLS_DB_TABLE_NEXTDEC
-		yourls_update_options_to_14();
-		// Now upgrade to 1.4.1
-		yourls_redirect_javascript( yourls_admin_url( "upgrade.php?step=1&oldver=1.4&newver=1.4.1&oldsql=200&newsql=210" ) );
-		break;
-	}
-}
-
-/**
- * Update options to reflect new version
- *
- */
-function yourls_update_options_to_14() {
-	yourls_update_option( 'version', '1.4' );
-	yourls_update_option( 'db_version', '200' );
-
-	if( defined('YOURLS_DB_TABLE_NEXTDEC') ) {
-		$table = YOURLS_DB_TABLE_NEXTDEC;
-		$next_id = yourls_get_db()->fetchValue("SELECT `next_id` FROM `$table`");
-		yourls_update_option( 'next_id', $next_id );
-		yourls_get_db()->perform( "DROP TABLE `$table`" );
-	} else {
-		yourls_update_option( 'next_id', 1 ); // In case someone mistakenly deleted the next_id constant or table too early
-	}
-}
-
-/**
- * Create new tables for YOURLS 1.4: options & log
- *
- */
-function yourls_create_tables_for_14() {
-	$ydb = yourls_get_db();
-
-	$queries = array();
-
-	$queries[YOURLS_DB_TABLE_OPTIONS] =
-		'CREATE TABLE IF NOT EXISTS `'.YOURLS_DB_TABLE_OPTIONS.'` ('.
-		'`option_id` int(11) unsigned NOT NULL auto_increment,'.
-		'`option_name` varchar(64) NOT NULL default "",'.
-		'`option_value` longtext NOT NULL,'.
-		'PRIMARY KEY (`option_id`,`option_name`),'.
-		'KEY `option_name` (`option_name`)'.
-		');';
-
-	$queries[YOURLS_DB_TABLE_LOG] =
-		'CREATE TABLE IF NOT EXISTS `'.YOURLS_DB_TABLE_LOG.'` ('.
-		'`click_id` int(11) NOT NULL auto_increment,'.
-		'`click_time` datetime NOT NULL,'.
-		'`shorturl` varchar(200) NOT NULL,'.
-		'`referrer` varchar(200) NOT NULL,'.
-		'`user_agent` varchar(255) NOT NULL,'.
-		'`ip_address` varchar(41) NOT NULL,'.
-		'`country_code` char(2) NOT NULL,'.
-		'PRIMARY KEY (`click_id`),'.
-		'KEY `shorturl` (`shorturl`)'.
-		');';
-
-	foreach( $queries as $query ) {
-		$ydb->perform( $query ); // There's no result to be returned to check if table was created (except making another query to check table existence, which we'll avoid)
-	}
-
-	echo "<p>New tables created. Please wait...</p>";
-
-}
-
-/**
- * Alter table structure, part 1 (change schema, drop index)
- *
- */
-function yourls_alter_url_table_to_14() {
-	$ydb = yourls_get_db();
-	$table = YOURLS_DB_TABLE_URL;
-
-	$alters = array();
-	$results = array();
-	$alters[] = "ALTER TABLE `$table` CHANGE `id` `keyword` VARCHAR( 200 ) NOT NULL";
-	$alters[] = "ALTER TABLE `$table` CHANGE `url` `url` TEXT NOT NULL";
-	$alters[] = "ALTER TABLE `$table` DROP PRIMARY KEY";
-
-	foreach ( $alters as $query ) {
-		$ydb->perform( $query );
-	}
-
-	echo "<p>Structure of existing tables updated. Please wait...</p>";
-}
-
-/**
- * Alter table structure, part 2 (recreate indexes after the table is up to date)
- *
- */
-function yourls_alter_url_table_to_14_part_two() {
-	$ydb = yourls_get_db();
-	$table = YOURLS_DB_TABLE_URL;
-
-	$alters = array();
-	$alters[] = "ALTER TABLE `$table` ADD PRIMARY KEY ( `keyword` )";
-	$alters[] = "ALTER TABLE `$table` ADD INDEX ( `ip` )";
-	$alters[] = "ALTER TABLE `$table` ADD INDEX ( `timestamp` )";
-
-	foreach ( $alters as $query ) {
-		$ydb->perform( $query );
-	}
-
-	echo "<p>New table index created</p>";
-}
-
-/**
- * Convert each link from 1.3 (id) to 1.4 (keyword) structure
- *
- */
-function yourls_update_table_to_14() {
-	$ydb = yourls_get_db();
-	$table = YOURLS_DB_TABLE_URL;
-
-	// Modify each link to reflect new structure
-	$chunk = 45;
-	$from = isset($_GET['from']) ? intval( $_GET['from'] ) : 0 ;
-	$total = yourls_get_db_stats();
-	$total = $total['total_links'];
-
-	$sql = "SELECT `keyword`,`url` FROM `$table` WHERE 1=1 ORDER BY `url` ASC LIMIT $from, $chunk ;";
-
-	$rows = $ydb->fetchObjects($sql);
-
-	$count = 0;
-	$queries = 0;
-	foreach( $rows as $row ) {
-		$keyword = $row->keyword;
-		$url = $row->url;
-		$newkeyword = yourls_int2string( $keyword );
-		if( true === $ydb->perform("UPDATE `$table` SET `keyword` = '$newkeyword' WHERE `url` = '$url';") ) {
-			$queries++;
-		} else {
-			echo "<p>Huho... Could not update rown with url='$url', from keyword '$keyword' to keyword '$newkeyword'</p>"; // Find what went wrong :/
-		}
-		$count++;
-	}
-
-	// All done for this chunk of queries, did it all go as expected?
-	$success = true;
-	if( $count != $queries ) {
-		$success = false;
-		$num = $count - $queries;
-		echo "<p>$num error(s) occured while updating the URL table :(</p>";
-	}
-
-	if ( $count == $chunk ) {
-		// there are probably other rows to convert
-		$from = $from + $chunk;
-		$remain = $total - $from;
-		echo "<p>Converted $chunk database rows ($remain remaining). Continuing... Please do not close this window until it's finished!</p>";
-		yourls_redirect_javascript( yourls_admin_url( "upgrade.php?step=2&oldver=1.3&newver=1.4&oldsql=100&newsql=200&from=$from" ), $success );
-	} else {
-		// All done
-		echo '<p>All rows converted! Please wait...</p>';
-		yourls_redirect_javascript( yourls_admin_url( "upgrade.php?step=3&oldver=1.3&newver=1.4&oldsql=100&newsql=200" ), $success );
-	}
-
-}
-
-/**
- * Clean .htaccess as it existed before 1.4. Returns boolean
- *
- */
-function yourls_clean_htaccess_for_14() {
-	$filename = YOURLS_ABSPATH.'/.htaccess';
-
-	$result = false;
-	if( is_writeable( $filename ) ) {
-		$contents = implode( '', file( $filename ) );
-		// remove "ShortURL" block
-		$contents = preg_replace( '/# BEGIN ShortURL.*# END ShortURL/s', '', $contents );
-		// comment out deprecated RewriteRule
-		$find = 'RewriteRule .* - [E=REMOTE_USER:%{HTTP:Authorization},L]';
-		$replace = "# You can safely remove this 5 lines block -- it's no longer used in YOURLS\n".
-				"# $find";
-		$contents = str_replace( $find, $replace, $contents );
-
-		// Write cleaned file
-		$f = fopen( $filename, 'w' );
-		fwrite( $f, $contents );
-		fclose( $f );
-
-		$result = true;
-	}
-
-	return $result;
-}