Firefox 55 and tab mix plus

[cool11]

After updating to ff version 55, tab mix plus seems to stop working properly.
It does not load tab sessions.
So, it is impossible to load my tabs environments and work efficiently.

Am I the only one with this problem?
Is this a bug of ff, or an incompatibility?
How it can be solved?

 

[SaSaSushi]

Seems to still be working for me in FF55, albeit now labeled as "Legacy Mode". Saved sessions load fine.

 

[cool11]

Where is located this 'legacy' mode?

 

[SaSaSushi]

In Add-on settings.

 

[cool11]

Finally I have been able to update my ff manually, downloading the dmg.
Now I have 55.0.1, and tab mix plus seems to work properly.
Not sure if it is because of .01 ff subversion.

But having the trouble I described above, I decided to search a little bit more for discovering what is going on. I have been worried from what I read in the latest comments on macupdate, regarding ff addons/extensions.
Please take a look
https://www.macupdate.com/app/mac/10700/firefox

Where do we going regarding ff and our beloved addons?
What should I expect, and which are the best choices to be taken into account, to be prepared for the future?

 

[cool11]

I can't understand what is going on.
While ff with tab mix plus seems to work,
everytime I open ff, it opens not only all my tabs,
but extra windows too!
I close the extra windows, leaving only one with my tabs,
I close ff(so the final session is one without the extra windows),
but when I open ff again,
the useless extra windows are there again!

Any ideas?