1964 PAT (Personalized Array Translator) on IBM 1620
1966 APL\360 (source available)
1968 APL\1130
1969 APL\700 for Burroughs B6700/7700 (continues until 1995)
1970 APL\5500 (source available)
1973 SCAMP Prototype   
1974 APL 5100, MCM/70
1976 CDC APL2 for Control Data 6000 series
1976 APL\11 appears for Unix v6, many versions follow
1977 APL/S for VideoBrain
1979 APL\11 (improved version) for Unix v6 (written in C language, source available)
1979 APLSF for PDP-20 runs under TOPS-20
1981 MicroAPL for SuperPET
1983 APL/PC version 1 for IBM PC DOS
1984 APL-80 for TRS-80 Model III, written by Phelps Gates
1987 APL/Z for Altair Z80 CP/M 
1988 Aplus originally for SunOS, later on for Linux, source available
1989 APL2/6000 for IBM RISC System 6000, I-APL
1989 APL interpreter for MSDOS and also BBC Micro, Atari ST by Paul Chapman
1990 APL.68000 for Amiga, Atari ST, etc
1992 port of APL\11 to Linux by Michael Cain (source available)
1997 IBM APL2 for Windows
1998 OpenAPL derived from APL\11 by Branko Bratkovic
1999 Amiga port of APL\11 (source available)
1999 Sharp (Soliton) APL for Linux
2013 GNU APL (source available)