diff --git a/etc/schema/mysql-upgrades/2.5.0.sql b/etc/schema/mysql-upgrades/2.5.0.sql
new file mode 100644
index 000000000..08a05c096
--- /dev/null
+++ b/etc/schema/mysql-upgrades/2.5.0.sql
@@ -0,0 +1,5 @@
+# Icinga Web 2 | (c) 2017 Icinga Development Team | GPLv2+
+
+ALTER TABLE `icingaweb_group_membership` MODIFY COLUMN `username` varchar(254) COLLATE utf8_unicode_ci NOT NULL;
+ALTER TABLE `icingaweb_user` MODIFY COLUMN `name` varchar(254) COLLATE utf8_unicode_ci NOT NULL;
+ALTER TABLE `icingaweb_user_preference` MODIFY COLUMN `username` varchar(254) COLLATE utf8_unicode_ci NOT NULL;
diff --git a/etc/schema/mysql.schema.sql b/etc/schema/mysql.schema.sql
index c124374ea..3e877975d 100644
--- a/etc/schema/mysql.schema.sql
+++ b/etc/schema/mysql.schema.sql
@@ -14,7 +14,7 @@ CREATE TABLE `icingaweb_group`(
 
 CREATE TABLE `icingaweb_group_membership`(
   `group_id`   int(10) unsigned NOT NULL,
-  `username`   varchar(64) COLLATE utf8_unicode_ci NOT NULL,
+  `username`   varchar(254) COLLATE utf8_unicode_ci NOT NULL,
   `ctime`      timestamp NULL DEFAULT NULL,
   `mtime`      timestamp NULL DEFAULT NULL ON UPDATE CURRENT_TIMESTAMP,
   PRIMARY KEY (`group_id`,`username`),
@@ -23,7 +23,7 @@ CREATE TABLE `icingaweb_group_membership`(
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 CREATE TABLE `icingaweb_user`(
-  `name`          varchar(64) COLLATE utf8_unicode_ci NOT NULL,
+  `name`          varchar(254) COLLATE utf8_unicode_ci NOT NULL,
   `active`        tinyint(1) NOT NULL,
   `password_hash` varbinary(255) NOT NULL,
   `ctime`         timestamp NULL DEFAULT NULL,
@@ -32,7 +32,7 @@ CREATE TABLE `icingaweb_user`(
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
 
 CREATE TABLE `icingaweb_user_preference`(
-  `username` varchar(64) COLLATE utf8_unicode_ci NOT NULL,
+  `username` varchar(254) COLLATE utf8_unicode_ci NOT NULL,
   `section`  varchar(64) COLLATE utf8_unicode_ci NOT NULL,
   `name`     varchar(64) COLLATE utf8_unicode_ci NOT NULL,
   `value`    varchar(255) NOT NULL,
diff --git a/etc/schema/pgsql-upgrades/2.5.0.sql b/etc/schema/pgsql-upgrades/2.5.0.sql
new file mode 100644
index 000000000..813928143
--- /dev/null
+++ b/etc/schema/pgsql-upgrades/2.5.0.sql
@@ -0,0 +1,5 @@
+/* Icinga Web 2 | (c) 2017 Icinga Development Team | GPLv2+ */
+
+ALTER TABLE "icingaweb_group_membership" ALTER COLUMN "username" TYPE character varying(254);
+ALTER TABLE "icingaweb_user" ALTER COLUMN "name" TYPE character varying(254);
+ALTER TABLE "icingaweb_user_preference" ALTER COLUMN "username" TYPE character varying(254);
diff --git a/etc/schema/pgsql.schema.sql b/etc/schema/pgsql.schema.sql
index ae92725fa..4638fc50a 100644
--- a/etc/schema/pgsql.schema.sql
+++ b/etc/schema/pgsql.schema.sql
@@ -35,7 +35,7 @@ ALTER TABLE ONLY "icingaweb_group"
 
 CREATE TABLE "icingaweb_group_membership" (
   "group_id"   int NOT NULL,
-  "username"   character varying(64) NOT NULL,
+  "username"   character varying(254) NOT NULL,
   "ctime"      timestamp NULL DEFAULT NULL,
   "mtime"      timestamp NULL DEFAULT NULL
 );
@@ -57,7 +57,7 @@ CREATE UNIQUE INDEX idx_icingaweb_group_membership
 );
 
 CREATE TABLE "icingaweb_user" (
-  "name"          character varying(64) NOT NULL,
+  "name"          character varying(254) NOT NULL,
   "active"        smallint NOT NULL,
   "password_hash" bytea NOT NULL,
   "ctime"         timestamp NULL DEFAULT NULL,
@@ -77,7 +77,7 @@ CREATE UNIQUE INDEX idx_icingaweb_user
 );
 
 CREATE TABLE "icingaweb_user_preference" (
-  "username" character varying(64) NOT NULL,
+  "username" character varying(254) NOT NULL,
   "name"     character varying(64) NOT NULL,
   "section"  character varying(64) NOT NULL,
   "value"    character varying(255) NOT NULL,