Simplify the following text for a Grade 6 native English-speaking person.
Original: Microsoft released Service Pack 1 ( SP1 ) on August 15 , 2000 , Service Pack 2 ( SP2 ) on May 16 , 2001 , Service Pack 3 ( SP3 ) on August 29 , 2002 and its last Service Pack ( SP4 ) on June 26 , 2003 .
Simplified: Windows 2000 has received four full service packs and one rollup update package following SP4 , which is the last service pack . These were : SP1 on 15 August 2000 , SP2 on 16 May 2001 , SP3 on 29 August 2002 and SP4 on 26 June 2003 .