lms 7.9 no line in menu on boom

Despite enabling the line in plugin and making sure the menu item is active for the boom player, the boom doesn't show the option, from either the on screen menu or the LMS web's control page. In fact, neither corresponds to the player configuration.

The boom is on firmware 57
The server is

Logitech Media Server Version: 7.9.0 - 1462256937 @ Tue May 3 06:40:36 UTC 2016

Server HTTP Port Number: 9000
Operating system: Debian - EN - utf8
Platform Architecture: x86_64-linux
Perl Version: 5.22.1 - x86_64-linux-gnu-thread-multi
Audio::Scan: 0.95
Database Version: DBD::SQLite 1.34_01 (sqlite 3.7.7.1)
Total Players Recognized: 3

is it a known bug ? I've not found any thread on the subject