Apple Computer on Friday began testing changes it has made to its popular Software Update mechanism, which is built into versions of the Mac OS X operating system.

The changes were reportedly incorporated into a new seed of Mac OS X 10.3.4 labeled Mac OS X 10.3.4 build 7H51a.

One of the major tests includes Software Update's ability to download and update itself.

"Mac OS X 10.3.4 build 7H51a includes changes to the Software Update application," the company reportedly told testers in a set of seed notes. "To help test these changes, we are delivering this build through Software Update."

According to sources, Apple has not seeded the Mac OS X 10.3.4 build 7H51a via its iMercury ftp distribution system. The only way to obtain the build is by running Software Update from a prior seed of Mac OS X 10.3.4.

Apple last seeded Mac OS X 10.3.4 build 7H50 on Wednesday, May 5th.