Updates for 2026-Jan-01 (#708)

* Move optional steps for testing VMs out of README.md file
This may help avoid new users being confused that they must follow
those instructions.

Signed-off-by: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>

* Add 2025-Jan-30 versions of source code for install.sh

Signed-off-by: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>

* Updates for 2026-Jan-01

Signed-off-by: Andy Fingerhut <andy.fingerhut@gmail.com>

---------

Signed-off-by: Andy Fingerhut <andy_fingerhut@alum.wustl.edu>
Signed-off-by: Andy Fingerhut <andy.fingerhut@gmail.com>

Author: jafingerhut

vm-ubuntu-24.04/install.sh

@@ -26,6 +26,7 @@ print_usage() {
     1>&2 echo "usage: $0 [ latest | <date> ]"
     1>&2 echo ""
     1>&2 echo "Dates supported:"
+    1>&2 echo "    2026-Jan-01"
     1>&2 echo "    2025-Nov-01"
     1>&2 echo "    2025-Oct-01"
     1>&2 echo "    2025-Sep-01"
@@ -45,11 +46,17 @@ else
 fi
 
 case ${VERSION} in
+    2026-Jan-01)
+	export INSTALL_BEHAVIORAL_MODEL_SOURCE_VERSION="2bdd0b7b2b2ae89faf2720f2158e9842bc6d2dd2"
+	export INSTALL_PI_SOURCE_VERSION="5689c91a8a7423781267b27d8b166c49a53904ff"
+	export INSTALL_P4C_SOURCE_VERSION="11d746d94a45694968802675bd9444dfcd029545"
+	export INSTALL_PTF_SOURCE_VERSION="05f46c3873feb2213df29743be3d9a9e34d5559b"
+	;;
     2025-Nov-01)
 	export INSTALL_BEHAVIORAL_MODEL_SOURCE_VERSION="2bdd0b7b2b2ae89faf2720f2158e9842bc6d2dd2"
 	export INSTALL_PI_SOURCE_VERSION="5689c91a8a7423781267b27d8b166c49a53904ff"
 	export INSTALL_P4C_SOURCE_VERSION="a97290474ce3d183b1f6bc4ca4959ebbcdb09b3b"
-	export INSTALL_PTF_SOURCE_VERSION=""
+	export INSTALL_PTF_SOURCE_VERSION="05f46c3873feb2213df29743be3d9a9e34d5559b"
 	;;
     2025-Oct-01)
 	export INSTALL_BEHAVIORAL_MODEL_SOURCE_VERSION="68f4a978f465fd76e98fcdecb762981843fb7310"