Sergey "Symnok", one of the real enthusiasts in the Symbian community in 2020, has penned a useful tutorial on getting access to Telegram messaging via a somewhat circuitous route - see the quote and link below. Using Symbian handsets in 2020 for anything meaningful is always going to be an exercise in frustration, but hey, it's good to have a hobby and breaking through the tech restrictions of a long-unsupported OS is a challenging one!

From Sergey's tutorial:

On your Symbian phone, install Lightbulb or Mail.Ru Agent Jabber/XMPP clients. You may use other clients too but some of them may not support Telegram.

19.   Connect to internet

20.   Configure your jabber account (tgtest@jabb.im on Lightbulb in this example)

21.   You will get authorization requests from all your Telegram contacts and telegram.jabbim.com
If you do not get these requests, restart your Symbian Jabber/XMPP client

 

22.   At the end your Jabber client will get all your Telegram contacts.
Do not remove telegram.jabbim.com . You must have this contact in contact list!

The steps are convoluted but fun to follow. For a rainy day, perhaps?