Hello Stephane,
Sadly no, Firefox for Android doesn't have a "Check for updates" button yet, but it's planned feature:
https://bugzilla.mozilla.org/show_bug.cgi?id=1810177

New fixed version 27.2 should auto-update within 24h (Firefox checks for addon updates every 24h, so you should receive the update within this time).
Best Regards,
Juraj Mäsiar