The Magyar Nemzeti Bank (Central Bank of Hungary) is in the process of replacing all its banknotes. The 10,000- and 20,000-forint notes have already been replaced. On 1 March 2017 the new 2,000- and 5,000-forint banknotes were released to the public, according to this press release.
The new 2,000-forint has an image of Prince Gábor Bethlen on the front and Gábor Bethlen among his scientists on the back. The note has an issue date of 15 November 2016 and is 154 mm x 70 mm. For an overview of ecurity features see this helpful site.
The 5,000-forint note has portrait of Count István Széchenyi on the front and Széchenyi's mansion at Nagycenk on the back. This note also has an issue date of 15 November 2016 and is the same size: 154 mm x 70 mm. Security features can be found here.
Banknotenews.com reports that a new 1,000-forint note will be issued in the second half of 2017.