Are these still Progress M1 vehicles or has the model evolved on since then?
Progress M-M series (400 Series SC's: No. 400-No. 430) is latest Progress version.
Progress MS series (400 Series SC's: No. 431+) which is in development is currently, to my knowledge, the last planned version of the Progress series before the switch to the new spacecraft design. Excluding Progress M-UM (No. 303), which is planned on Soyuz-2-1B, Progress MS is the first version of the Progress and Soyuz spacecrafts designed to support launches on the Soyuz-2 launcher series (Soyuz-2-1A & Soyuz-2-1B versions only). There now 10 or less Soyuz-U PVB launchers left to start, so only Soyuz-FG, Soyuz-2-1A, and Soyuz-2-1B versions are available to fly the new Progress MS series as well as the new, but lately uncertain Soyuz MS (Soyuz TMA-MS) series.
The first scheduled launch in the Progress MS series is on 30 July 2015.
Here is an incomplete schedule i created from Anik's Schedule of ISS flight events (part 2), Anik's Plan of Russian space launches (part 2), and From PM from Stan Black:
30 July 2015 – Progress MS (No. 431) – Soyuz – Baikonur
22 October 2015 – Progress MS-2 (No. 432) – Soyuz – Baikonur
22 February 2016 – Progress MS-3 (No. 433) – Soyuz – Baikonur
2016 (TBD) – Progress MS-4 (No. 434) – Soyuz – Baikonur
2016 (TBD) – Progress MS-5 (No. 435) – Soyuz – Baikonur
2016 (TBD) – Progress MS-6 (No. 436) – Soyuz – Baikonur
2017 (TBD) – Progress MS-7 (No. 437) – Soyuz – Baikonur
2017 (TBD) – Progress MS-8 (No. 438) – Soyuz – Baikonur