[SignalR] [Java] Document minimum Android API levels

[analogrelay]

We should add the following notes to our Java Client documentation regarding compatibility:

• The SignalR Java Client will run on Android API Level 16 and above.
• Connecting through the Azure SignalR Service will require Android API Level 21 and above because the Azure SignalR Service requires TLS 1.2 and does not support SHA-1-based cipher suites. Android added support for SHA-256 (and above) cipher suites in API Level 20.

[bradygaster]

created pr: #9342

[Rick-Anderson]

@bradygaster no need to explicitly call out PR in the issue, it's added automagically when you refer in the PR.

[bradygaster]

Closing this issue as we have a PR open for it now in the Java client doc.

[deepaksharma1992]

Hi, we were thinking of using SignalR with our android client application. But requirement is to use TLS1.2. Will it be possible to use it on android devices below API 20. Thanks.

[analogrelay]

It's my understanding that no, if you require TLS1.2 you must use Android API Level 20 or above. That's a general Android restriction, not specific to SignalR.

[deepaksharma1992]

Hi, yes but we have to enable it on devices below 20, but i am not sure if it is available for the android sigalR library

[analogrelay]

We don't test TLS 1.2 on Android applications below level 20. It may be possible to enable it, but we don't officially support it at this time.

[deepaksharma1992]

Thanks, for your response.

[deepaksharma1992]

I am not sure, about I was looking into the code and it is internally using OkHttp. If we could enable the TLSSocketFactory in the client builder. Maybe it will start supporting TLS1.2 on devices below API 20. Will update you as soon as found something.