May I draw your attention to Jean-Luc's release notes from the latest stable version of Nxt's NRS software:
Change log:
This is a critical bugfix release. Everyone is required to update.
Jean-Luc is good at looking out for Nxters security (like when the critical Jetty bug was announced and Jean-Luc patched Nxt within 24 hours in version 1.4.16) So.... it makes sense to listen to him
When a large botnet or virus is found on many computers around the world making them vulnerable, the biggest most responsible antivirus companies have patches out very quickly and you are expected to upgrade
for your own good.
If not, you are putting yourself at risk as a known exploit might be used against you. This is the same situation
The nodes that aren't running the latest NRS,
you are at risk from a known bug. Not to try and scare you but you are putting yourself at risk when there is no need to
So... moral of the story: Do the smart thing and
upgrade to the latest version! You can do that here:
https://nxtforum.org/nrs-releases/LATEST STABLE VERSION IS: NRS v1.5.10 as of 7th June 2015 That is all