OpenIndiana Distribution

Hi all,
I have checked mysql mediator on my /hipster installation:

$  uname -rosv
SunOS 5.11 illumos-def4fac588 Solaris

$ pkg mediator mysql
MEDIATOR            VER. SRC. VERSION IMPL. SRC. IMPLEMENTATION
mysql               system    10.1    system     mariadb

$ pkg list| grep mariadb
database/mariadb-101                              10.1.21-2017.0.0.0         i--
database/mariadb-101/client                       10.1.21-2017.0.0.0         i--
database/mariadb-101/library                      10.1.21-2017.0.0.0         i--
database/mariadb-55                               5.5.54-2017.0.0.0          i--
database/mariadb-55/client                        5.5.54-2017.0.0.0          i--
database/mariadb-55/library                       5.5.54-2017.0.0.0          i--

So, tried to remove mariadb-55 (since I do not need 2 instances), but:

$ pfexec pkg uninstall -v database/mariadb-55/library database/mariadb-55/client database/mariadb-55
Creating Plan (Solver setup): -
pkg uninstall: Unable to remove 'database/mariadb-55/library@5.5.54-2017.0.0.0' due to the following packages that depend on it:
  benchmark/sysbench@0.4.12-2017.0.0.0
  library/apr-util/dbd-mysql@1.5.3-2017.0.0.1
  library/python/python-mysql-27@1.2.5-2017.0.0.0
  library/qt4@4.8.7-2017.0.0.0
  library/qt5@5.8.0-2017.0.0.0
  web/php-56/extension/php-mysql@5.6.27-2017.0.0.0
  web/php-56/extension/php-mysqli@5.6.27-2017.0.0.0
  web/php-56/extension/php-pdo_mysql@5.6.27-2017.0.0.0
  web/php-70/extension/php-mysqli@7.0.17-2017.0.0.0
  web/php-70/extension/php-pdo_mysql@7.0.17-2017.0.0.0

it looks that many packages are still referencing it.
Somehow, I was expecting that mariadb 10.1 will replace mariadb 5.5 instance.

Am I wrong?
Regards.