Here is a summary of one of my previous posts:
1957-60: Series I (orange wheels, orange diamond-mesh grille, round muffler, grille-mounted headlights, oval model decals on side panels; 1959+ models had 3-bar black grille and slightly different decals)
1960-62: Series II (white wheels, white square-mesh grille, round muffler, metal hood decals, square model decal on lower half of gas tank, still had grille-mounted headlights I believe)
1962-64: Series III (white wheels, white square-mesh grille, oval muffler, full-length white hood decals, fender-mounted headlights, mechanical updates, engine updates)
1964-67: Series IV (same appearance as Series III, major mechanical updates such as gear driven hydraulic pump mounted where belt pulley used to be, provided for full-time live dual hydraulics whenever engine was running; Category II 3-point hitch option; external rams on rear lift arms)
These are the major highlights. I am recalling this from memory, so there may be a few things missing. The D19 was produced from 1961 to 1964 - no series designation. The D17 diesel used the 262 diesel throughout production (1957-67), although various design improvements were made to this engine in later models. Ditto on D19. The additional HP of the D19 diesel (66 HP vs. 52 HP on the D17 diesel) was obtained by turbocharging the 262 diesel in the D19. The 262 gas in the D19G achieved 71 HP.