Zx-81 has, as expected released an update for PSPMSX v1.5.1. The MSX Emulator. Just like his other emulators zx-81 has applied IRDA Joystick box support to PSPMSX.
Develpoer notes / Changelog:

For those who have never heard about IRDA joystick project, the goal was to connect your old DB9 joystick (compatible with Atari , Amiga, Amstrad etc [...]

Zx-81 has released an update to PSPMSX his MSX and MSX2 emulator . Its now compatible with 5.00 M33, version. This new version (version 1.4.1) is a  text editor that allows you to save notes on the games.
Changelog:
* Finally fix issue with “Home -> Exit” !
* Text editor to write your own comments on games
* [...]

PSP Devopler ZX-81 has released PSPMSX v1.30 with added gzip support allowing users to gzip the roms down from 700kbs to around 50kb. Great for users with little Memory Stick Pro space left. Also the normal run-of-the mill bugfixes in this release. For full details see the changelog after the read more tab.
Source: Zx-81

Zx-81 latest MSX Emulator called PSPMSX v1.5.1. Without a doubt the best PSP MSX emulator there is.
Develpoer notes / Changelog:

PSPMSX v1.5.1 : MSX Emulator changelog :
- IRDA Joystick box support
- Add “IRDA joystick” device support for both
DB9 Joystick and Atari Paddle
- Add menu for IRDA joystick settings and keys mapping
- Add option to choose between [...]