Forum Set up new vB4 site with vB5-format URLs
 

I set up our new forum on vB4 and want to use the same format as vB5 to make a future upgrade as easy as possible. Or can I keep using the vB4 URL format after upgrading to vB5?

Examples:

forum url

vb4: /forums/1-forum-name
vb5: /forum/category-name/forum-name

thread url

vb4: /threads/1-thread-title
vb5: /forum/category-name/forum-name/1-thread-title

What's the best way to accomplish this? I actually like the vb4 URL format so it is easier to move threads, forums and categories without breaking the thread URLs.