Really old one... started originally in 1993 with Deluxe Paint 2e under DOS (pirated), then enhanced a bit in Photoshop 2.5.1 (pirated) under windows 3.1 (pirated).
Then in 2005 opened up under Photoshop 7 (pirated), duplicated, imported back into Deluxe Paint 2e. This is just 256 colors, BTW.
So is it 2005 then? Dunno maybe later. Checked the file date - January 12, 2006.
So when is Deluxe Paint being ported to Windows? LOL. Never.