why doesn't bitesms ask me to update to 6.3???

I think you have to have the beta repo in your sources. Do you?

http://cydia.bitesms.com

 

I don't really know I don't have it installed but I'll give it a go now.

Worst case scenario is you can go back to 6.2

 

i only use the betas and never downgrade to the current release. i have been on 6.3 beta for months and yes its as good as a final release. in fact the latest beta that came out about a week ago will be the final release iirc.