Altirra 2.0 Test 21 is released. Altirra is an Atari 8 bit Emulator on the Windows/DOS platform. Altirra emulates several models of the 8-bit Atari computers. This includes the the 800, 800XL, and 130XE versions. It has a lot of options, and compatibility is decent especially given the emulator's early stages. It also supports some copy protected games properly in emulation.

Altirra 2.0 Test 21 Changelog:

bugs fixed: HLE: Screen setup now matches the display list and playfield addressing of the stock OS ROM. HLE: Fixed cartridge handling so that cartridges are run after disk boot completes. HLE: Added known RTS instruction at $E4C0. HLE: CIO now allows SPECIAL commands to be issued on a closed IOCB.

Download: Altirra 2.0 Test 21
Source: Here