Update version numbers

README.md

@@ -12,12 +12,12 @@ Key course sites:
 References and Resources:
 * [GitLab Flavored Markdown (GFM)](https://docs.gitlab.com/ee/user/markdown.html)
 * [Java Archive (.jar)](https://docs.oracle.com/javase/tutorial/deployment/jar/basicsindex.html) for sharable/runnable software libraries
-* [Java SE JDK download](http://www.oracle.com/technetwork/java/javase/downloads/index.html) (JDK 8 or 12)
+* [Java SE JDK download](http://www.oracle.com/technetwork/java/javase/downloads/index.html) (JDK 16)
 * [Netbeans](http://www.netbeans.org) (version 8.2 or 12), [Using Git Support in NetBeans IDE](https://netbeans.org/kb/docs/ide/git.html) 
 and [Video of Cloning a Git Repository Using NetBeans IDE](https://netbeans.org/kb/docs/ide/git_nb_ssh_screencast.html)
-* [Open-DIS Repository](https://github.com/open-dis) and [Distributed Interactive Simulation: The Missing Handbook](https://github.com/open-dis/DISTutorial/blob/master/README.md)
+* [Open-DIS Repository](https://github.com/open-dis) (specifically open-dis7-java) and [Distributed Interactive Simulation: The Missing Handbook](https://github.com/open-dis/DISTutorial/blob/master/README.md)
 * [Savage Developers Guide](https://savage.nps.edu/Savage/developers.html) resources for [Cygwin](https://savage.nps.edu/Savage/developers.html#Cygwin), [DIS](https://savage.nps.edu/Savage/developers.html#DIS) and [telnet](https://savage.nps.edu/Savage/developers.html#telnet)
 * [Sequence Diagram](https://en.wikipedia.org/wiki/Sequence_diagram) and [Timing Diagram (UML)](https://en.wikipedia.org/wiki/Timing_diagram_(Unified_Modeling_Language)) on Wikipedia
 * [WireShark](https://wireshark.org) and [WireShark Tutorial for Beginners](https://www.youtube.com/watch?v=TkCSr30UojM) video by Anson Alexander
-* [X3D-Edit](https://savage.nps.edu/X3D-Edit/#Downloads) as Netbeans Plugin including [DIS PDU Player/Recorder](https://savage.nps.edu/X3D-Edit/images/DisPlayerRecorderPanel.png) and [ESPDU Generator](https://savage.nps.edu/X3D-Edit/images/DisEspduTestPanelDemo.png) (currently requires Netbeans version 8.2)
+* [X3D-Edit](https://savage.nps.edu/X3D-Edit/#Downloads) as Netbeans Plugin including [DIS PDU Player/Recorder](https://savage.nps.edu/X3D-Edit/images/DisPlayerRecorderPanel.png) and [ESPDU Generator](https://savage.nps.edu/X3D-Edit/images/DisEspduTestPanelDemo.png) (currently requires Netbeans version 12.4)
 * [X3D for Web Authors](http://x3dgraphics.com) book, examples and slidesets including [X3D Distributed Interactive Simulation (DIS)](http://x3dgraphics.com/slidesets/X3dForAdvancedModeling/DistributedInteractiveSimulation.pdf)