The approach (without keeping a plug in all the time) could be:
- Disable automatic serial numbers for topics
- Import everything with the old ids
- Re-enable serials, starting at a number larger than the MAX currently used
But ok, I get the point - it’s easier with the permalinks feature. I have found many posts with specific questions about this, mostly people trying to get their regexps right, but I haven’t found any page documenting the actual mechanism in general… is there such a page?
As always, thanks a lot for your help.