I have Win XP running 7-ZIP 32 bit version. Also, Win 7 running 32 bit version. Plus, Win 8.1 running 64 bit version. An encrypted, zipped Excel spreadsheet on Win XP / 32 bit version was successfully opened by Win 8.1 / 64 bit version into Excel.
So, there may be issues for fancy high-tech programmers - but - for us end-users with multiple computers running various Win versions - it looks like - everything works GREAT.