Ability to fallback to v2 encoding

[Horusiath]

It's a small quality of life improvement, but it sometimes might happen that we're passing a binary message encoded using v2 encoding over a method/decoder set to v1. It's actually possible to detect v2 encoding as it's starting with [0,0,...] (which means empty update in v1) followed by more bytes. With that we could optionally fallback to v2 in some cases.