Late in 2014, SWPC migrated all of its web presence to a modernized system. The main impetus for this migration was to allow us to more easily modify content and add new features. When we migrated to the new web services for our content, we made the decision to keep the old SWPC website (legacy-www.swpc.noaa.gov) available to allow our customers time to migrate to the new one. At that time, we made a commitment to keep the old site around for no less than 60 days. Four years later, that website is still in existence but it will be turned off very soon.
We kept the old site around as it was not requiring any effort on the part of SWPC to do so. Given new IT security requirements however, SWPC must disable the old website. We will turn off this old website on 05 September 2018 at 1500 UTC (11am ET). Note that this will not impact any of the content on the new SWPC website (www.swpc.noaa.gov or spaceweather.gov).
If you have any questions on this, please feel free to reach out to us at the following email address: swpc.customersupport@noaa.gov