DEV and QA on different patch levels - transport problems?

Hi All,

What are the potential problems of having a DEV system on a LOWER patch level than QA?

My major concern is with transporting an OSS note from DEV to QA. Could this potentially overwrite an SAP object on QA with an older version from DEV? or are there checks in place that will prevent this from happening?

For example you apply an OSS note of DEV which modifies program AAA. On QA the program AAA does not match DEV as QA is on a higher patch level and program AAA has been improved. When we transport the changes to AAA from DEV to QA will program AAA be overwritten with the outdated version from DEV or are there check in place to stop this?????

Che