If you didn’t see the updates to the official post for this issue already -
I’m really sorry, but this issue won’t be resolved until the next game update version 4.3.5 as it needs an update to the game version/application to fix. The issue is caused by a problem notifications and doesn’t mean we won’t be supporting older iOS devices in the future.
Please follow this article to keep up to date with the problem and for some workarounds that might help (some players have been able to link to other devices to keep playing).
If you haven’t already please submit a ticket if you are affected by this issue so we can organize compensation when the issue is resolved.