As part of investigating support, I ran Crowd 2.3.4 against Oracle XE 11.2.0 using ojdbc6.jar 11.2.0.3.0 without seeing any issues. I used the Oracle 10g dialect.
As the CROWDKB article indicates, there may be a problem after upgrading from 10g to 11g; I haven't tested this scenario.
Full support would require testing this upgrade, automating an acceptance test and updating the UI to indicate that dialect is for 10g and 11g.
Excellent timing. I can use version 2.5 for our production roll out then.