You have to buy the J! 4/5 template again for your template.
If you already have it for J! 3, you can enter a discount code when purchasing using the following link.

https://www.joomla51.com/blog/item/joomla-4-template-update-timeline

Hello!

Thank you! I didn't know this..
If you had an Achley51 template for Joomla 3 and purchased a new Achley51 template for Joomla 4/5. What's the best way to update the template now? In Joomla 3? And then switch to Joomla 4?

Are there any rules for transferring a site from Joomla template 3 to Joomla template 4/5? Template Achlet51

Hello

I would suggest updating your Joomla installation to Joomla 4/5 first and then update your template. Note that your website will not work correctly until you have also updated your template.

Also ensure that the Joomla Backward Compatibility plugin is enabled. This plugin is enabled by default so shouldn't be anything to worry about.

Ciaran