Changes in synapse v0.28.1 (2018-05-01) ======================================= SECURITY UPDATE * Clamp the allowed values of event depth received over federation to be [0, 2**63 - 1]. This mitigates an attack where malicious events injected with depth = 2**63 - 1 render rooms unusable. Depth is used to determine the cosmetic ordering of events within a room, and so the ordering of events in such a room will default to using stream_ordering rather than depth (topological_ordering). This is a temporary solution to mitigate abuse in the wild, whilst a long solution is being implemented to improve how the depth parameter is used. Full details at https://docs.google.com/document/d/1I3fi2S-XnpO45qrpCsowZv8P8dHcNZ4fsBsbOW7KABI/edit# * Pin Twisted to <18.4 until we stop using the private _OpenSSLECCurve API.