diff --git a/retriever/database.sql b/retriever/database.sql
index 68480cfd..6139fea4 100644
--- a/retriever/database.sql
+++ b/retriever/database.sql
@@ -6,11 +6,11 @@ CREATE TABLE IF NOT EXISTS `retriever_rule` (
        PRIMARY KEY (`id`),
        KEY `uid` (`uid`),
        KEY `contact-id` (`contact-id`)
-) DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
+) DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
 
 CREATE TABLE IF NOT EXISTS `retriever_item` (
        `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
-       `item-uri` varchar(800) CHARACTER SET ascii COLLATE ascii_bin NOT NULL,
+       `item-uri` varbinary(255) NOT NULL,
        `item-uid` int(10) unsigned NOT NULL DEFAULT '0',
        `contact-id` int(10) unsigned NOT NULL DEFAULT '0',
        `resource` int(11) NOT NULL,
@@ -20,7 +20,7 @@ CREATE TABLE IF NOT EXISTS `retriever_item` (
        KEY `item-uid` (`item-uid`),
        KEY `all` (`item-uri`, `item-uid`, `contact-id`),
        PRIMARY KEY (`id`)
-) DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
+) DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
 
 CREATE TABLE IF NOT EXISTS `retriever_resource` (
        `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
@@ -28,15 +28,15 @@ CREATE TABLE IF NOT EXISTS `retriever_resource` (
        `contact-id` int(10) unsigned NOT NULL DEFAULT '0',
        `type` char(255) NULL DEFAULT NULL,
        `binary` int(1) NOT NULL DEFAULT 0,
-       `url` varchar(800) CHARACTER SET ascii COLLATE ascii_bin NOT NULL,
+       `url` varbinary(800) NOT NULL,
        `created` timestamp NOT NULL DEFAULT now(),
        `completed` timestamp NULL DEFAULT NULL,
        `last-try` timestamp NULL DEFAULT NULL,
        `num-tries` int(11) NOT NULL DEFAULT 0,
        `data` mediumblob NULL DEFAULT NULL,
        `http-code` smallint(1) unsigned NULL DEFAULT NULL,
-       `redirect-url` varchar(800) CHARACTER SET ascii COLLATE ascii_bin NULL DEFAULT NULL,
+       `redirect-url` varbinary(800) NOT NULL,
        KEY `url` (`url`),
        KEY `completed` (`completed`),
        PRIMARY KEY (`id`)
-) DEFAULT CHARSET=utf8 COLLATE=utf8_bin
+) DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci;
diff --git a/retriever/retriever.php b/retriever/retriever.php
index 83c357d3..714a33a1 100644
--- a/retriever/retriever.php
+++ b/retriever/retriever.php
@@ -32,7 +32,19 @@ function retriever_install() {
 	Addon::registerHook('contact_photo_menu', 'addon/retriever/retriever.php', 'retriever_contact_photo_menu');
 	Addon::registerHook('cron', 'addon/retriever/retriever.php', 'retriever_cron');
 
-	if (DI::config()->get('retriever', 'dbversion') != '0.14') {
+	if (DI::config()->get('retriever', 'dbversion') == '0.14') {
+		if (!DBA::e("ALTER TABLE `retriever_rule` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci") ||
+		    !DBA::e("ALTER TABLE `retriever_item` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci") ||
+		    !DBA::e("ALTER TABLE `retriever_item` MODIFY `item-uri` varbinary(255) NOT NULL") ||
+		    !DBA::e("ALTER TABLE `retriever_resource` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci") ||
+		    !DBA::e("ALTER TABLE `retriever_resource` MODIFY `url` varbinary(800) NOT NULL") ||
+		    !DBA::e("ALTER TABLE `retriever_resource` MODIFY `redirect-url` varbinary(800) NOT NULL")) {
+			Logger::warning('Unable to update database tables: ' . DBA::errorMessage());
+			return;
+		}
+		DI::config()->set('retriever', 'dbversion', '0.15');
+	}
+	if (DI::config()->get('retriever', 'dbversion') != '0.15') {
 		$schema = file_get_contents(dirname(__file__).'/database.sql');
 		$tables = explode(';', $schema);
 		foreach ($tables as $table) {