ungrading to 11.2.0.3 soon, have clients that use Oracle 11g and lower client.

Wewill be ungrading to 11.2.0.3 soon.  We are at 10.2.0.4 at the moment.   We have users/clients accessing the database using JDBC, Oracle clients at different versions.  I was wondering if anyone has had user issues accessing the 11.2.03 database using lower versions of the Oracle client.   Is there a workaround, patch that can be applied for any issues with users using lower versions of the client.    We have users all over the US that access the database and will be impossible to get all upgraded to the 11g client.