Parallel installation of OJS3 before upgrade


We are going to make an upgrade from OJS2.4.7.1 to OJS3.x. We would like to do that by making the parallel installation of OJS3. Once we tidy up this new, parallel installation we would then replace the old version with the new one. I assume such process should not pose any problem but I would like if somebody could confirm if my step-by-step reasoning below is correct:

  1. Make a copy of an old database and the complete files_dir.
  2. Download and decompress the OJS3.x package in the new folder
  3. Copy and public/ folder from the old installation to the new one
  4. Edit the and make the following modifications:
  • change the base_url to correspond to the new location
  • change database parameters
  • change files_dir to correspond to the new location
  1. Upgrade OJS database by running a web-based script as instructed in documentation.

What I do not understand is what I need to do with In the documentation a synchronization is mentioned but it is not clear to me.

Is the above procedure correct? I assume we would have then two copies of the same journal. The old copy would work normally and the new one we could work on and once we are satisfied with it just the replace the old copy. Did I forget or miss something?


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Hi @zmandic,

Your steps look OK, I have upgraded several OJS installations same way. Note that during this upgrade process the ‘old’ OJS has to be shut down, otherwise there can be changes not transferred to the new OJS.

The is just template/example of the file. No need to bother with it.

Best regards, Primož

Thank you very much Primož!
I intend first to make one testing upgrade to learn the process and for Editors to get familiar with the new version. Once we are satisfied with it we will delete it and repeat the procedure once again with old version “shut down”.

Hi all,

FYI - the in OJS 3 will certainly contain new OJS directives not found in your 2.4 config file. You should go forward with the TEMPLATE as your new but merge in your database connection settings, base_url, and so on. Failing to do so may result in unexpected behaviour.


Thanks Jason!
But, I am not sure I understand what exactly I need to do with it and how?


Hey Zoran,

You can leave it alone, but a copy of it becomes your new file, along with any specific settings found in your current one. Make sense?



sorry but I still do not get it. Could you just explain me what to do apart from:

  1. copying old from old to new location
  2. modifying to correspond to the new database and file location

Should I copy from the old to the new location and do I need to modify it?


Hi Zoran,

The from your old 2.4 installation can be completely ignored. No longer needed. The new that comes with OJS 3 becomes your new You’ll then edit it and enter in the correct details for your database and such.

The file is never looked at by OJS when OJS is running. It’s just there for your reference.


Ok, thanks. I understand now.
I do not need to copy from the old version but modify the new as needed.



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Hi Zoran,

You have mentioned that you require a test new installation for editors to get used to before you completely switch over. By going the above route, you will not get a parallel installation, unless you set us a new subdomain or domain. For what you want to work, you need to create a new subdomain/domain and do it.
Also, you need to give a different SSID to the new site, otherwise session cookie mixup will happen.

And , it is good practice to ensure that your files_dir is OUTSIDE your OJS web folder.



Thanks Kmnair!
What is SSID and how I change it for particular site or folder?

Sorry for the delay. But I did not get a ping from the forum.

The session cookie name is part of the file. You can see it as the third item under General Settings. The default value is given below.
; Session cookie name
session_cookie_name = OJSSID

This may be changed by adding some character to it like OJSSIDNEW or similar to prevent session cookie mixup.