Hi I've had my Axim X50v with Arm 624MHz for about 3 years and would like to move up to WM5 but haven't been able to find much about upgrading or if it's even possible.
Welcome to Aximsite! On the top bar of the forum area you will see the word "Search." Click there, enter "upgrade WM5" and you'll find hundreds, if not thousands, of posts on upgrading. There are pros and cons to that upgrade on the X50v.
Yes it is possible to upgrade your X50v to WM5 and even to WM6.
Many people have found that it isn't worth the bother to go to WM5 because it is slower and less functional than 2003 on the X50.
However if you wish to do it you would need to get hold of a WM5 upgrade CD.
Dell no longer supply them but you can find them on ebay.
I believe some members here can supply you with the files you would need via PM, but I will leave it to them to tell you if they can.
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God used to be my copilot but we crashed in the mountains and I had to eat him to survive.