Switching Pi3 from 32-bit to 64-bit

I’m having an early spring clean of some of my Pi’s, and as part of that I want to move a few docker containers from another Pi onto my current DietPi set-up.

Most of them moved fine, but one (calibre-web) is being a pain as they’ve stopped support for armv7 and only seem to support armv8.

Currently I’m running the 32-bit version of DietPi on the Pi3 (which is defaulted I believe to 32-bit install?), so I was wondering if it’s possible update it to the 64-bit one, and if so how easy it is (or isn’t) to do so? I’ve seen a few threads about it here, but most of them are 3 or more years old and semi pre-date the official release of the 64-bit OS’s.

In the meantime I’ve found an older container for calibre-web, but it’s not been updated for a year and is still running the older 6.19 version of the server (the one from before Linuxserver stopped supporting Arm v7, back in April).

Can someone comment on what the current status of such an update/upgrade would be? I’d prefer not to have to rebuild everything if I can avoid it.

Short answer, this is not possible.

The only thing you could do, is to switch into a 64bit kernel mode. However this would still leave the whole system/userland with 32bit. And I guess your container would not being able to start.

Thanks - I thought that might be the case based on the old threads, but wanted to double check.

One to put on hold I think until I update that Pi3 to something newer, and the whole thing can have a rebuild at that point.