The new Informix release 11.70xC9 has been released in April 2017. The focus of the latest Informix release is on bug fixing only. 
You are interested to get details from the Fix list of Informix 11.70 xC9? Please click here:

http://www-01.ibm.com/support/docview.wss?uid=swg27049414

The Fix list shows you the corresponding Authorized Program Analysis Reports (APARs) sorted by numbers.