Simplify the following text for a Grade 12 native English-speaking person.
Original: After a version of a software package has remained in unstable for a certain length of time ( depending on the urgency of the software 's changes ) , that package is automatically migrated to the testing distribution .
Simplified: After a version of a software package has remained in unstable for a certain length of time ( depending on how urgent the changes are ) , that package is automatically moved to the testing distribution .