An updated description of planned GMD flight tests (last update was my post of April 12, 2015) as best I can reconstruct them. Between now and mid-2021, it appears that MDA plans five intercept and one non-intercept test of the GMD system.
FTG-15 (1Q FY 2017). This is scheduled to be the first intercept test since FTG-06b in July 2014. It will be the first GMD intercept test against an ICBM-range target (range greater than 5,500 km). The target will include countermeasures. FTG-15 will also will be the first flight and intercept test of the new production CE-II Block-I version of the Exo-Atmospheric Kill Vehicle (EKV) and the first flight test of the upgraded C2 booster. According to Admiral Syring, in this test “…we’re getting now out to the long-range and closing velocities that certainly would be applicable from a North Korean or Iran type of scenario.” 
FTG-15 (Image source: MDA)
FTG-11 (1Q, FY 2018). This is to be the first salvo (multiple interceptors fired at a single target) test of the GMD system. In it, both a CE-I and CE-II equipped Ground-Based Interceptor (GBs) will be fired at a single ICBM-range target. The test is described as an “operational” one. In its 2015 annual report, DOT&E noted that this test would implement its previous year’s recommendation that the CE-I EKV be re-intercept tested following the failure of FTG-07 in July 2013.
FTG-11 (Image source: MDA). Date has slipped from that on image.
GM CTV-03 (3Q, FY 2018). First flight test of the new Redesigned Kill Vehicle (RKV). It is not an intercept test. If this test is successful, the MDA will proceed to build eight further RKVs for developmental purposes.
This test will also likely be the first flight test of the new 2/3 stage selectable GBI booster. (For discussion of 3/3 stage booster, see my post of February 2, 2016.) According to a March 2015 report, a two-stage non-intercept test was planned for the 3rd quarter of FY 2018, so it seems likely that this test is being combined with the first non-intercept test of the RKV.
FTG-17 (3Q, FY 2019). First intercept test of the new RKV. The target is an ICBM-range missile with countermeasures. If this test is successful, MDA plans to proceed with a competition for the procurement of 37 additional RKVs.  This will also the first intercept test of the two-stage version of the 2/3 stage selectable GBI booster.
FTG-17 (Image source: MDA)
FTG-18 (2Q, FY 2020). Intercept test of RKV with 2/3 stage selectable booster against an ICBM-range target with countermeasures. According to Admiral Syring, although this test will happen after the production decision on the RKV-equipped GBIs, it will occur before their deployment.
FTG-18 (Image source: MDA)
FTO-04 (3Q FY 2021). This will be the first GMD test against two simultaneous targets. In an operational test, two GBI interceptors (a CE-I and a CE-II) will attempt to intercept two targets with IRBM and ICBM ranges. At least the IRBM will include countermeasures. FTO-04 is a BMDS system operational test that will also likely involve a mix of Aegis, Aegis Ashore, THAAD and/or Patriot systems. The GMD portion of FTO-04 has formerly been referred to as FTG-13.
FTO-04 (Image source: MDA)
 Vice Admiral James D. Syring, “Ballistic Missile Defense System Update,” presentation at the Center for Strategic and International Studies, January 19, 2016. Video available at: http://csis.org/event/ballistic-missile-defense-system-update-0.
 Date of this test from statement of Vice Admiral J.D. Syring, Subcommittee on Strategic Forces, Senate Armed Services Committee, April 13, 2016. Available at: http://www.mda.mil/global/documents/pdf/FY17_Written_Statement_SASC_SFS_MDA_VADM_Syring_13042016.pdf,
 Syring statement, 2016.
 DOT&E Annual Report 2015, p. 372. Available at: http://www.dote.osd.mil/pub/reports/FY2015/pdf/bmds/2015gmd.pdf
 Jason Sherman, “MDA Proposes Revised $2 Billion, Five Year RKV Project to Execute New Acquisition Strategy,” Inside Defense SITREP, March 2, 2016.
 Scott Maocione, “MDA Puts $51 Million in Budget To Develop Two-stage Booster,” Inside Defense SITREP, March 12, 2015.
 Sherman, “MDA Proposes Revised.”
 Syring, CSIS presentation.
 From the April 14, 2016 hearing of the Strategic Forces Subcommittee of the House Armed Services Committee:
ROGERS: I thank the gentleman.
Admiral Syring, what are the risk of legislating or setting in stone a requirement to conduct to set a number of tests before the RKV final production decision?
SYRING: The — we have — we have, obviously in this budget, we have a proposal that are — and in our acquisition strategy that was signed by Mr. Kendall that there’ll be one non- intercept and one intercept test conducted to inform a production decision by him, not me. There’ll be another intercept in ’20 that will happen before really anything is fielded.
 Amy Butler, “Pentagon Plans Three Ambitious GMD ‘Firsts’,” Aviation Week and Space Technology, December 18, 2014; prepared testimony of J. Michael Gilmore, Director of Operational Test and Evaluation, Strategic Forces Subcommittee, Senate Armed Services Committee, March 25, 2015.