Hey there,

I am really sorry for the delay of this reply as it is a public holiday for us here.

Yes, you will lost your previous customisation if you upgrade to Payplans 4.0.

It would be best is clone your current live site to another test site, then try upgrade to Payplans 4.0 from your test site.

So you can manage it back your customisation work compatible with Payplans 4.0.

Thank you, Arlex Wong! I am very afraid of giving problems and I believe that I will not upgrade to this new version, although I consider it important.

You are most welcome Adriano. Just for your information, PayPlans 4 is a major upgrade and we have rewritten everything from scratch, making it much easier to maintain as well as creating template overrides.