You can place the serialized model in a raw storage, like an S3 bucket if you're on AWS. In S3's case, you can use bucket versioning which might prove helpful. Then setup some sort of trigger. You can definitely get creative here, and I've thought about this a lot. In practice, the best options I've tried are:

Set up an endpoint that when called will go open the new model at whatever location you store it at. Set up a webhook on the storage/S3 bucket that will send a quick automated call to the given endpoint and auto-load that new item
Same thing as #1, but instead you just manually load it. In both cases you'll really want some security on that endpoint or anyone that finds your site can just absolutely abuse your stack.
Set a timer at startup that calls a given function nightly, internally running within the application itself. The function is invoked and then goes and reloads.

Could be other ideas I'm not smart enough (yet!) to use, just trying to start some dialogue.
I made an API for my AI model but I would like to not have any down time when I update the model. I search a way to load in background and once it's loaded I switch the old model with the new. I tried passing values between sub process but doesn't work well. Do you have any idea how can I do that ?
Load new model in background