Hello,

I just upgraded from Zenphoto 1.5.7 / PHP 7.4 to 1.6.5 / PHP 8.1.
Here's a few comments on the process. This is just a feedback, if it can help. This is not a support request :-)

Of course I had a few issues, mainly because of my setup or my competencies.
For example, I tried to go straight from 1.5.7 to 1.6.5... it didn't work :-) (and skipping versions is clearly not recommended by the Zenphoto doc. My bad).

I was in Zenphoto 1.5.7 on PHP 7.4. I downloaded all versions from this page:
https://www.zenphoto.org/news/older-versions-archive/
(1.5.8, 1.5.9, 1.6, 1.6.1, etc up to 1.6.5 from the front page).
I upgraded Zenphoto 3 times first: 1.5.7 => 1.5.8 => 1.5.9 => 1.6
Then I upgraded PHP 7.4 => 8.1
Then I upgraded Zenphoto again, 5 times between 1.6 and 1.6.5.
Between each upgrade I did a few tests of the admin page and the site.

Now 2 feedbacks :

1. Each time, the setup lists a few files to delete. Once there was zp-core/zp-extensions/mobileTheme/Mobile_Detect.php, I told the installer to delete it: then the site was not loading anymore. The debug.log said a "Failed opening required" ERROR. I restored the file and it worked.
2. Several times, I got the message, on the setup.php page, that skipping version is not recommended. This is strange because I was upgrading from 1.6.4 to 1.6.5, and it wrote I was skipping 91 versions or something.

So far it seems to work fine, you can visit here:
https://www.cactuspro.com/conophytum-lithops/

Have a nice week-end :-)

Thanks for the feedback:

1. Those lists are not directly meant to be deleted. It triggers on the file time being off the majority of the files that "might" indicate something is wrong. You should not delete them right away. Probably we should take this out as no "normal" user will have enough knowledge of the system what to do exactly.

2. That was a bug in older versions as the internal catalogue calculating that accidentally was missing some versions.

Glad you managed it overall!

Hmmm.. yeah my galleries are still on version 1.5.7 and running PHP 7.4.33. Luckily my webhost still allows that version of PHP. My other sites are on PHP 8.1.31. Last time I tried doing upgrades, I ran into all kinds of issues so I just let it be.

Next time I try, I will just upgrade one version increase at a time and not upgrade the PHP version until later version 1.6.

Thanks for giving me a different method to try.

The step by step procedure @cactux used is actually the recommended upgrade way as mentioned on our install page. Since Version 1.5.x does not support PHP 8 you have to first be on 1.6 to switch PHP to PHP 8/8.1/8.2. https://www.zenphoto.org/news/requirements/#--requirements-for-older-versions

@markRH: It would be interesting what issues that were. 1.5.7 is over 4 years old now…

I personally have successfully upgrade quite old versions directly. The only issues were third party tools respectively custom made themes that required updates naturally. Besides that these custom themes were created by me it was mostly minor stuff to do like replacing deprecated functions and such. The more complicated custom code and the more versions are left out the more work has to be done as it culumates. That's common for any CMS. But we're quite backwards compatible.

Zenphoto 1.6 generally still runs on PHP 7.4 although we primarily only test on PHP 8.2.