Hi

What version number of Firefox for Android do you have installed on your device?

I have just had a look in the latest version and I can save at least 21 Collections.

81.1.4 (Build #2015768387) AC: 57.0.7, 68343a885 GV: 81.0.1-20200930150533 AS: 61.0.13

I just added collections and now recognize that all the old collections are no longer there.

I strongly recommend that you update to the most recent version of Firefox for Android available from the Google Play store.

no difference - but does not answer the question.

how many collections can you use?

The upper limit is determined by the capacity of your device, but certainly on my own Android device you can have more than 20 Collections.

sorry but what you write is vague and partially wrong the device has no limit for collections.

the question was: how can i restore old collections that I have not deleted myself but firefox just dropped them without asking me.

i think the question only can be handled by a developper who knows the code and can tell if there is an algorithm deleting former collections, when many new ones are added. And who can say if there is a way to restore those. Everything else is not helpful and does not answer the question. KR

It will not be possible to recreate the collections that you lost. I recommend that you use the most recent version of Firefox for Android to prevent this from happening again in the future.