marketrelations@nyiso.com writes to the NYISO_TECH_EXCHANGE Discussion List:

To Market Participants

The official change from the 'Old' website to the 'New'
website will occur at 10:00 AM May 8.  We expect the
change to take about 10 minutes to complete.  The change
will only affect the public portion of the website and should
be transparent to most users.

If you are on the public website at the time of the switch, you
may need to reload/refresh the page you are viewing.  Also,
if you are downloading public data directly or through a script file,
errors may occur.  Simply reinitialize the download to correct
any errors that may have occurred.

If after about 10:10, 10:15 AM you are still experiencing difficulties,
please contact your Customer Relations Representative
or call 1-518-356-6060.

Thank You
The Website Refresh Team