[FEATURE] Support device (re)hydration

[menturion]

Support device (re)hydration to overcome the issue that encrypted messages cannot be read if the receiving user was offline while the sender sent messages.

See e.g. ... https://github.com/vector-im/element-web/issues/2996 https://github.com/vector-im/element-web/issues/3825

I know that this feature has not been released officially/finally but device (re)hydration is already implemented in the matrix-react-sdk.

[notramo]

Being offline doesn't cause undecryptable messages.

Only if all devices are logged out.

[menturion]

That's not correct. If all clients are disconnected from network (i.e. being totally offline) you are not able to decrypt a message you received during this time.

[notramo]

Then it's a bug in Cinny. Hydrated devices are not for this. Please open another issue regarding this.

[kfiven]

Then it's a bug in Cinny.

Has not happened to me. @menturion you surely misunderstood the dehydrated device usage. MSC says "when a user has no logged-in devices when a message is sent, they are unable to receive incoming megolm sessions."

[menturion]

@kfiven

Many thanks for your message! Right, this is what I meant. We can change any above description text if this is misleading.

Device (re)hydration should be supported.

[akoranii]

Any progress on this? How to contribute to fix this issue? @ajbura @kfiven @menturion

[Leonscreative]

Hi, any progress with that? It will be great to resolve it asap because is blocking the User experience. Thanks

[sceboucher]

Following.