Might be you can refer below document which contains details about new features available in 10.4 version:
Also, there are few issues fixed in 10.4 version compared with lower versions.
From a high level they are basically the same. The only difference is 10.4 has additional options as far of connectors and some new services. But creating services, security and things like that are almost identical.
On a technical level the big differences are the supported operating system and DBMS versions as well as the version of the built-in JDK (except for AIX where a certain JRE must be installed on the whole system).
Also all command-line utilities offer some new functionality, and there may be some slight changes for existing options.
What is the exact background of your question?
Do you want to understand what trouble you have to await during an upgrade?
Informatica v10.4.0 will have bug fixes, new features included and more enhancements done in comparison to Informatica 9.6.1. You can refer the Release Notes of 10.4.0 to understand what are the issues that have been fixed, new features introduced and other known limitations.