Tandem Warsaw International Community
Download the Tandem app to read the Tandem's Telegram channel on your Android smartphones (just in case you don't want to install the Telegram app and join the Tandem channel)
http://tandeminternational.waw.pl/TandemWarsawInternationalCommunity.apk
Just for fun, a proof of concept: Tandem app that you can install on your Windows 10 PC. The app currently does nothing but can be further developed.
Cross compiled on Linux for Windows 32 bit :)
http://tandeminternational.waw.pl/tandemsetup.exe
Tandem Telegram channel (recommended): it cannot be easily shut down by any government and user information and activities cannot be collected just by one click or automatically:
https://t.me/s/tandemwarsawinternational
Tandem on Eventbrite:
https://www.eventbrite.com/o/tandem-warsaw-international-community-24904785648
Tandem on Meetup
https://www.meetup.com/expats-warsaw/
Tandem social media channels (unrecommended) (they can be easily shutdown without any notice with loss of all content):
Facebook page:
https://www.facebook.com/TandemEvening.Warszawa
Facebook main group:
https://www.facebook.com/groups/tandem.evening
Google blog:
http://warszawatandem.blogspot.com/
Youtube channel (rarely used):
https://www.youtube.com/channel/UCwG5W5-eDr_LZYIZokiH6rw
Tandem has several other language specific groups on Facebook:
The only one currently useful is the group for online meetings: