Notice 2017-75 provides Guidance under Section 409A for pre-2009 Section 457A deferrals,

Document Excerpt

This notice provides guidance on the application of Internal Revenue Code (Code) section 409A with respect to amounts that are includible in income pursuant to section 801(d)(2) of the Tax Extenders and Alternative Minimum Tax Relief Act of 2008, Div. C of Pub. L. No. 110-343 (TEAMTRA). Section 801(a) of TEAMTRA added section 457A to the Code. Section 457A generally applies to deferred amounts that are attributable to services performed after December 31, 2008. However, if section 457A does not apply to a deferred Amount solely because the amount is attributable to services performed before 2009, section 801(d)(2) of TEAMTRA provides that the amount is includible in gross income in the later of the last taxable year beginning before 2018 or the taxable year of vesting. This guidance provides that a nonqualified deferred compensation plan that is subject to the provisions of Code section 409A will not fail to meet the requirements of section 409A solely because payments of deferred amounts under the plan are accelerated to pay income taxes on the amounts includible in income pursuant to section 801(d)(2) of TEAMTRA. This notice is intended to supplement, not supersede or modify, the guidance provided in Notice 2009-8, 2009-4 IRB 347 (Jan. 26, 2009).

Link

https://www.irs.gov/pub/irs-drop/n-17-75.pdf