Support for MSC3440

[matrixbot]

This issue was originally created by @ryester19 at matrix-org/dendrite#2938.

Description:

Now that Element Web and Android has enabled threading by default, Dendrite should fully support this. From what I've read and witnessed, enabling MSC2836 isn't enough for an Element client to see a Dendrite homeserver as supporting threading.

[matrixbot]

This comment was originally posted by @clokep at matrix-org/dendrite#2938 (comment).

enabling MSC2836 isn't enough for an Element client to see a Dendrite homeserver as supporting threading.

MSC2836 is a different proposal than what was merged (and is essentially unrelated to the threading in MSC3440).

Dendrite would need to support:

• MSC3440
• MSC3715
• MSC3771
• MSC3773
• MSC3816
• MSC3856

As well as any MSCs which those depend on.

[matrixbot]

This comment was originally posted by @notramo at matrix-org/dendrite#2938 (comment).

Why does it depend on MSC3865?

[matrixbot]

This comment was originally posted by @clokep at matrix-org/dendrite#2938 (comment).

Why does it depend on MSC3865?

I typed, it is MSC3856, not MSC3865. I've updated the list in the comment above to reflect this.