A possibility. Did you accidentally/accidentally buy the J3 version of the template?
Do you want to update J3 template to J4 template?
I think Ciaran needs more info...

I am quite sure it's the J4 version of the template. I had been upgrading the website from J3 to J4. After having done this successfully, I tried to install J51_Valencia_J4, hoping to replace the existing J51_Valencia_J3. But then, installing J51_Valencia_J4 failed with the error message
«Downgrade from version 1.1 to 1.0.0 not allowed».

I helped myself by uninstalling J51_Valencia_J3 first. After doing so, I could install J51_Valencia_J4 without any further issue. For me this issue is resolved. But I think Ciaran should have a look at the version numbers. I don't think that a downgrade error messege should occur when you upgrade :-)

Kind regards
Chris

Hi Chris

Thank you for reporting this issue.

I have just created an update for this template which should resolve this issue for you. For details on updating your template may I suggest the following article.. https://joomla51.com/tutorials/joomla-basics/updating-your-joomla-template

If the issue persists after updating, may I suggest sending temporary administration access to your Joomla installation to info@joomla51.com and we will examine this issue further. For our reference please paste a link to this post in your email.

Ciaran