SagerNet
The universal proxy toolchain for Android
...Using an MTU larger than the upstream interface will only improve speed in some scenarios and may result in UDP packet loss. According to the gfw.report et al's research, when connecting to the impacted VPSs, GFW is likely to block binary protocols unless it is an HTTP, TLS, or SSH connection, or the first 6 bytes of data sent from client to server can be interpreted as printable characters. This suggests in addition to TLS encryption, HTTP Header, this kind of censorship can also be temporarily evaded by only sending printable characters in the first 6 bytes of data.