MariaDB 10.1.27 was released very recently and is also in CustomBuild but do not update:
https://mariadb.org/mariadb-10-1-27-now-available/
A regression was discovered after the release of MariaDB 10.1.27. It has been pulled from the downloads system, but some mirrors may still have it. Do not download or install this version. Stay with MariaDB 10.1.26 until 10.1.28 is released
https://mariadb.org/mariadb-10-1-27-now-available/