34 C.F.R. § 363.53
(b) Prior to assisting the individual in transitioning from supported employment services to extended services, the designated State unit must ensure—
(2) The source of extended services for the individual has been identified in order to ensure there will be no interruption of services. The providers of extended services may include—
(ii) The designated State unit, in the case of a youth with a most significant disability, in accordance with requirements set forth in 34 CFR 361.5(c)(19) and this part for a period not to exceed four years, or at such time that a youth reaches the age of 25 and no longer meets the definition of a youth with a disability under 34 CFR 361.5(c)(58), whichever occurs first. For youth who still require extended services after they can no longer receive them from the designated State unit, the designated State unit must identify another source of extended services for those youth in order to ensure there will be no interruption of services. The designated State unit may not provide extended services to individuals with the most significant disabilities who are not youth with the most significant disabilities.
(Authority: Sections 7(13), 12(c), and 604(b) of the Rehabilitation Act of 1973, as amended; 29 U.S.C. 705(13), 709(c) and 795i)