AIX 6.1 / 7.1/ 6.5.9:
splunkforwarder-6.5.9-eb980bc2467e-AIX-powerpc.tgz
Release Notes
http://docs.splunk.com/Documentation/Forwarder/6.5.9/ReleaseNotes
UF download link
https://www.splunk.com/page/previous_releases/universalforwarder#ppcaix
latest UF -
Splunk Universal Forwarder 7.2.1 ---- AIX 7.1, 7.2
https://www.splunk.com/en_us/download/universal-forwarder.html#tabs/aix
http://docs.splunk.com/Documentation/Forwarder/7.2.1/Forwarder/Installanixuniversalforwarder
As you are a new user to Splunk Answers, you can upvote the answers/comments,
if this answer resolved your query, you can select this answer and "accept" it as the answer, so that this question will be moved to answered queue. Happy Splunking!