well, thats good to know - I guess I didn't follow the 9.1.3.0 to 9.1.3.1 release that closely ! But I think its still a good practice that a customer shouldn't implement a tools release until the 3rd release - ie, a 9.1.4.2 release - given the following information :
1. The code set feeding into the .0 release is not tested by end-users and is very, very limited testing as part of Oracles QA process
2. The code set feeding into the .1 release (.0) is tested by a limited number of end-users, none of which are in production, and therefore on a limited platform set. It is likely that complex implementations are not tested through this codeset
3. The code set feeding into the .2 release (.1) is usually tested by pre-production implementations
4. The code set feeding into the .3 release (.2) usually has some production implementations
Therefore, if you're pre-production, feel free to implement the .1 release - but if you're a production customer, have a good rollback plan if you implement .2 - but its a safer bet to implement the .3
I am glad that Oracle is compressing the time for releases to come out to the public - but remember, you're running a financial system ! Not good to be a customer right on the cutting edge unless you have excellent internal support !