Currently the WeVoip app on Google Play was last updated 29 November 2019, with added support for S10 series phones.
Right now we have customers with S20 phones on which the app does not work, does anyone know if they will update the app anymore?

Also till when will new licence generating for OfficeServ be possible?

Given Samsung left the usa market, i'm not sure how much updates Wolli happen on wevoip.
You would have to speak to the distributors in your region about licensing. Given the eol of os7000 I would expect it would stop soon.