Here are relevant posts on updating from RW5 to RW6. If you search the forum you will find more posts on the topic.
HTH.
I suggest per realmac’s instructions: downloading 5.4.1, opening your projects and saving them, then they should open fine in RW 6. RW 5.4.1 does not have to be registered to open and save the project file. You will have to make sure your 3rd party plug-ins and stacks (if you’re using any) are also updated for RW 6. RW 6 uses a different extension for the project file your_project_name.rw6 as opposed to the RW 5.X project file your_project_name.rwsw
.rw6 files can only be opened by RW6, i believe .rwsw files will not open in RW6.
Once you download 5.4.1, launch it directly, then you’ll know that version is running, and then open your projects from within 5.4.1 and save them.
see this post as well: Importing RW 5 Projects into RW6. Read here first - #2 by Turtle
Update error on Rapid Weaver 5.3.2 going to RW6 - #10 by thang