@astghik No, looks like didn't update from 7.0.X before license expired. "You can continue to use your purchased addons for lifetime without any limitation in functions" but then having all plugins deactivate themselves because because they weren't updated seems like an intentional limitation in functions and a force to renew license to get the update to 7.1.0 so that they don't auto deactivate...
The bold text doesn't have any relation to the core free wpDiscuz plugin. It's related to the addons, and it is still valid. That's why you can continue to use your addons.
We're asking you to update the free core plugin. Nobody asks you pay or get any paid addon, just keep updating the free wpDiscuz plugin to be up to date. So just update the wpDiscuz plugin and continue to use your paid addons with expired licenses.
BTW, the 7.0.1 has an important bug-fix, which will not deactivate your expired addons, so it'll understand that your addons had been once activated and the addons were purchased legally. In other words the 7.1.0 version was released especially for cases like yours.