Hi there and welcome to our community
First, we would appreciate it if you would take a few moments and familiarize yourself with the link below. It's intended to help you get the best forum experience.
As for the issue of htm VS html, this is something you will need to manually change by editing the properties of each topic. Sorry. The thing is, there simply is no technical reason that a page requires to be named html. The only cases we have seen where it makes a difference are when a developer is simply being hard headed about it or when something has uniquely been set up at a company where the html file extension is actually required to make things work.
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