The UltraSPARC IV Jaguar and follow-up UltraSPARC IV+ Panther are microprocessors designed by Sun Microsystems and manufactured by Texas Instruments. They are the fourth generation of UltraSPARC microprocessors, and implement the 64-bit SPARC V9 instruction set architecture (ISA). The UltraSPARC IV was originally to be succeeded by the UltraSPARC V Millennium, which was canceled after the announcement of the Niagara, now UltraSPARC T1 microprocessor in early 2004. It was instead succeeded by the Fujitsu-designed SPARC64 VI.