A final rule issued by the General Services Administration amends the GSA Acquisition Regulation to revise GSAR Part 570, Acquiring Leasehold Interests in Real Property, and related solicitation provisions and contract clauses. The GSAR Case 2006-G508 final rule updates regulatory provisions that apply to lease transactions and provides sustainability guidance on implementing Executive Order 13514, Federal Leadership in Environmental, Energy, and Economic Performance, and the Guiding Principles for Federal Leadership in High Performance and Sustainable Buildings. Also, the rule deletes the dollar value of the simplified lease acquisition threshold and substitutes a reference to FAR 2.101 for information about the threshold. The rule moves advertising requirements from GSAR Part 505 to GSAR Part 570, since most of the guidance on advertising requirements contained in GSAR Part 505 relate to the leasing program, and it seeks to add clarity and improve readability.