Q. A program can only be yEnc v1.3 compliant if it supports CRC error checking, so does yProxy support CRC?
Yes. yProxy Pro supports CRC error checking.
However, because you can download individual messages from a multi-part message in any order through a proxy, or even through different connections, it would require a lot of overhead to do CRC error checking on multi-part messages. Therefore, yProxy Pro only supports CRC error checking for single-part messages! Since most multi-part messages, for simplicity, are still posted as single-part messages, yProxy will be able to use CRC most of the time.
yEnc's two benefits over UUEncoding are: smaller size, and CRC error checking. So, if you're using a yDecoder that does not support CRC, you're losing half of the benefit of yEnc.
Versions prior to yProxy Pro did not support CRC error checking. Please upgrade.