I'm about to commit a major change to the 'old' table in HEAD. There should ideally be no problems, but it's quite possible it will end up corrupting your database, deleting articles or their histories, or doing other bad things. There will almost certainly be minor bugs.
If you have anything important in a 1.4 version database, you MUST backup your database before updating or you WILL lose it!
You have been warned.
Kate.