I've noticed there is a v1.0 and v1.1 for the US release. Does anyone know what are the differences between those 2 versions?

I cannot find any page, except this one but doesn't help https://www.smspower.org/forums/17900-CastleOfIllusion#110171

This page suggests it's an input buffer on pause.

https://www.smspower.org/forums/15144-SMSCastleOfIllusionVersionDifferences

To update, https://tasvideos.org/3636S also says the clock bolt RNG is naturally UP on 1.1, but it isn't clear from explanation whether he implies this purely as a consequence of TAS optimal play.

@Quarbit, I know we were wondering how he achieved the library wall jump before the tea - I'll post in the TASvideos forums on these subjects and inquire further.

To be clear I doubt we'd ever know which runs on the board used 1.0 or 1.1 and I don't think it's an issue for existing runs, however, depending on what info we get, perhaps we may wish to discuss implications for future runs.