Block older clients about end_to_end_encryption

[tobiasKaminsky]

For android we need to change the useragent: nextcloud/android#1852
But then we could block all ownCloud clients and all Nexcloud <2.1 for E2E.

[rullzer]

I'm not sure we have to infrastructure around to fix this. But I do agree. However I would just block them in general if E2E is enabled.

[tobiasKaminsky]

Currently we use the same useragent "Mozilla/5.0 (Android) ownCloud-android/$versionNumber".
As ownCloud is on version 2.5 and we will release 2.1 we cannot block them that easily depending only on the versionNumber. So we need to change the user agent...

[tobiasKaminsky]

@rullzer what is missing on server side to do this?

[marinofaggiana]

I use : Mozilla/5.0 (iOS) Nextcloud-iOS/2.19.0

check E2E < 2.19.0

[georgehrke]

@camilasan @misch7 What version of the desktop client should we block?

[georgehrke]

@rullzer what is missing on server side to do this?

Not much, we can just listen on Sabre/DAV requests in check the user agent, no big deal.
Would should the error message be like?

[georgehrke]

it seems this was already worked on: https://github.com/nextcloud/end_to_end_encryption/blob/9e71e2d282ccd106cbe3f5f62ad60abd5d05d072/lib/UserAgentManager.php