You will be able to link to the old article, and replies to old articles will be redirected to a new thread with a link to the old article. The loss of functionality and inconvenience is unfortunate, however necessary to advance the forum software.
These old articles are stored only in HTML files, which are terribly difficult to synchronize among many servers. I'd like to move to a 100% database solution.
Why don't you convert your days to 26 hours, and then with the extra two hours a day you would have time to write a program that would convert the old data to the new format. . . ?