By AppleInsider Staff

Published: 12:00 PM EST

Apple Inc. this week began offering its developer community a new pre-release build of its upcoming Leopard operating system, sources tell AppleInsider.

Mac OS X 10.5 Leopard build 9A499 is believed to be the first widespread seeding of the software since June. At that time, Apple treated attendees at its annual developers conference to an exclusive preview of build 9A466, later broadening distribution of that same build to its vast Apple Developer Connection community.

According to people familiar with this week's near 7-gigabyte seeding, the new build is noticeably snappier than the one it replaces. Those same people, however, continue to report that software is rife with bugs, making it somewhat unstable.

"I'm recommending to other developers that they stick with the earlier 9A466 build," one said. "[The latest build] is very buggy."

For its part, Apple has already delayed Leopard once -- pushing it out to "October" from an introduction originally planned for June. The company attributed the delay to iPhone, saying it needed to borrow some key software engineering and QA resources from its Mac OS X team in order to make good on a promise to launch the handset by the end of June.

As part of its developers conference six weeks ago, Apple previewed what it called a "near feature complete" version of Leopard, introducing previously "top secret" features such as a new 3D application dock and file "stacks."