Unable to upgrade from 3.4 to 3.5

Software Support
1

Describe the issue or problem
Upgraded from 3.4 to 3.5. Last step reached “Upgrade Open Journal System,” and it directs me to my journal login to enter settings. However, this page does not load and instead I get error 500.

Steps I took leading up to the issue
For example:

  1. Opened the app via Kualo website.
  2. Clicked to upgrade Open Journal Systems and followed the steps.
  3. Changed Installed to On
  4. All went smooth until the last page where I needed to complete the upgrade.

What application are you using?
For example, OJS 3.5.0.4 is currently shown as installed. Previous version before upgrade was 3.4.0

I changed the Installed back to Off and got the following message
Upgrade unsupported. See the Upgrade Guide (https://docs.pkp.sfu.ca/dev/upgrade-guide) for details.

Screenshot 2026-05-12 at 2.57.05 PM
Screenshot 2026-05-12 at 2.57.05 PM2706×1240 131 KB

Screenshot 2026-05-12 at 2.56.56 PM
Screenshot 2026-05-12 at 2.56.56 PM2706×1240 312 KB

Additional information
Please add any screenshots, logs or other information we can use to investigate this problem.

2

Hi,
did you do a backup of your installation, files and database? Could you provide the last “Fatal error” message from error_log?

Edit: Right now, I can see that you downgrade back to OJS 3.4.0-5 on you website. Your website is working well now.
Best,
Radek

3

Thanks Radek. I reverted back while I figure what is the problem. I have tried to upgrade again today and faced some other issues. Right now I am stuch with the error message attached.

Screenshot 2026-05-13 at 6.15.45 PM
Screenshot 2026-05-13 at 6.15.45 PM2436×828 330 KB

4

Hi there,

the problem is caused by the PLN plugin. The PLN plugin has not been released for the OJS 3.5, yet. There is just some kind of pre-release of the plugin: Release PKP|PN 4.0.0-0 - OJS 3.5 (Pre-release) · pkp/pln · GitHub

So, right now, you have three possible solutions:

  1. if you are not using the plugin, you can delete it from the plugin gallery before the upgrade and try again. It is possible that there will be an another plugin which will cause a different error,
  2. you can try install the pre-released plugin right into the general folder and hope that it will works, there still could be an another plugin with a different error,
  3. or you can stay with OJS 3.4 and wait till the plugin will be released for OJS 3.5, then instal correct version of the plugin and try the upgrade again.

Hope it helps :slight_smile:

Good luck.

Best,

Radek