Arrest Warrants: Warrant with a Purge Date

My question involves criminal law for the state of: AZ, If a warrant has been issued for a DWI and has a purge date, what does that mean exactly. Eg.A warrant was issued in 2003 and has a purge date in 2008, has the case been dropped in 2008. thx

Arrest Warrants: Warrant with a Purge Date