Version 0.  If a client does not send a ver key on a request, it's assumed to support protocol Version 0. In protocol Version 0, textual information transmitted from or to the server is always assumed to be a stream of 8-bit bytes, not necessarily ASCII, but without any guarantee that the non-ASCII bytes are presented in any particular encoding. You can only upload such unknown8bit entries to personal journals. You cannot post an entry to a non-person account (a community) with international or special characters at all — unless you set Version 1.

Version 1.  Version 1 differs from Version 0 only by imposing additional requirements on the text transmitted through requests and responses; there aren't any changes in protocol modes. The additional requirements are that in a Version 1 request, the client must transmit all textual information as a stream of Unicode data encoded in UTF-8; the server must respond to Version 1 requests with Version 1 responses; in such Version 1 responses, the server must also transmit all textual information encoded in UTF-8; and the client must expect that and handle such responses correctly. In other words, all information transmitted via protocol when Version 1 is used is always encoded in UTF-8. UTF-8 is a representation of Unicode in a bytestream format compatible with ASCII. ^[19]