The update to Joomla 2.5.16 caused a problem with the ordering of articles when using the NewsFlash module.
If you have been using the Joomla Newsflash module to pull up most recent articles in a given category, you may have noticed the article order was reversed after updating your Joomla installation to the 2.5.16 version. And, there's nothing you can do to fix it.
I had this problem come up with several sites that I'd built (I should say... every site that I've built that utilizes the Newsflash module).
Give Joomla some credit... never, in all the years that I've been building Joomla websites, have I run across an issue with an update. So, I'll cut them some slack.
Using your FTP client or your host's file manager, simply upload and replace the folder "mod_articles_news" (including the sub-folders and files) under the module folder of your Joomla installation.
If you don't have a backup, here are the files. Unzip the file before uploading to your Joomla installation.
Note* I just tested it on one of my test installations and was able to successfully install it by uploading and installing the zip file through the Extension Manager > Install.
It worked for me.