MS Access 32/64 bit interoperability

I don't have a copy of 64 bit MS Access installed so I can't try this. I'm a developer looking at what's involved with adding support for 64 bit. I'm just using the MS Access database as a back-end.

I have a database made with 32 bit MS Access 2007, can you confirm that it can be directly opened in a 64 bit version of access? Must the file be upgraded?

If I have a database made with 64 bit MS Access version X, can it can be directly opened in a 64 bit version of Access version X? Must the file be upgraded?

thank you!