ICQ in 2025, on OS X and PowerPC

Running an ICQ client on your PowerPC machine (and OS X 10.1+), in 2025, is not really that hard considering the ICQ network has been shut down since 2024. Download the last version (3.4.23) of ICQ available for OS X and PowerPC architecture, and install it. The nina.chat people are nice enough to provide access to an ICQ service that will allow you to use the old clients. Problem is that you need to patch the server address inside your ICQ client, basically, all occurences of .icq.com will need to be changed into .nina.bz.

Open the /Applications/ICQ/ICQ 3.4 binary in a hex editor and look at offset 0x3EB926. Replace icq.com with nina.bz, do the same thing for the offset 0x3F2DED. Save the file and now your old ICQ client will work over the ICQ service provided by nina.chat.

Same thing can be achieved from a Terminal window using xxd:

$ cd /Applications/ICQ
$ cp "ICQ 3.4" "ICQ 3.4_backup"
$ echo 003EB926: 6E 69 6E 61 2E 62 7A | xxd -r - "ICQ 3.4"
$ echo 003F2DED: 6E 69 6E 61 2E 62 7A | xxd -r - "ICQ 3.4"

Enjoy ICQ.