Cache entire mailbox offline?

I am looking for a new IMAP mail client for Windows (I’ve had enough with Outlook and its corrupt .pst files) and I like the look of Mailspring. However, one of my top requirements is being able to store an offline copy of my entire mailbox (Gmail), which I can then incorporate in my backup routine.

Having read a few threads and comments from various dates, I’m left uncertain as to whether this is possible with Mailspring. It looks as though there was an unconfigurable age limit imposed at one point, possibly to maximise performance, but then I saw something suggesting that a configurable cache parameter may be introduced.

Can anyone confirm how much data the latest version will download and cache offline by default, and whether this can be changed by the user?

Thanks in advance.

:mega: Is there anybody out there? :wink: