You can choose to set a custom PDF reader in the General tab of preferences --> Open PDF using --> custom [1].

Then you can annotate the file and save it. If Zotero creates a copy of the file when you save your annotations, you might need to use Show file by right clicking the article in Zotero and make changes to the file in Zotero's storage. In Linux, that'll be in ~/Zotero.

[1] https://forums.zotero.org/discussion/1977/changing-the-defau...

No need to use Show File. You can just open the PDF from Zotero, annotate, and save.

It's a bit of a pain, but you can store `~/.local/share/okular/docdata/` in version control or your favourite cloud storage provider, and then you'll get synchronised annotations.

When I say a bit of a pain, I mean it - I switched to Mendeley with great sadness because its mobile application means I can read and annotate papers on my tablet and have it synchronised perfectly with my desktop.

On a semi-related note: the Mendeley mobile application makes selecting text a joy on a touchscreen with a kind of magnifying glass. I really wish it was built into Android system wide.

> you can store `~/.local/share/okular/docdata/` in version control

What kind of annotations are that? I think GP refers to document annotations, which are stored in the PDF file itself.

Annotations meaning notes, highlights, etc.

If they are stored in the file itself, that's news to me. Last time I used it, Okular didn't modify the actual PDF and considered that a feature.

You have to explicitly save the file after making the annotations. I've been doing this for years with Okular, indeed, Okular having out-of-file annotations is news to me :)

Oh, wow. That will make collaboration so much easier. I resorted to Adobe Reader on multiple occasions in the past...

Thanks!