I have a super old blog that I upgraded from 2.0.7 to 3.1 by upgrading over multiple versions. One of my biggest concerns was losing all the link juice from my legacy URLs but they were clearly made at a time when I hadn't considered how the URLs would need to change.
To my surprise I found that changing my permalink structure from
went really smoothly as WordPress automatically looked up the appropriate URL -- which is great.
But I'm wanting to know since Ive changed link structures, does it send 301 header messages so I dont lose link juice from 5+ year old links, or is there a way for me to force WordPress to do this for old URLs?