An older Symantec root certificate, SymRoot1, will expire on April 30, 2011. With an expired certificate, older LiveUpdate clients would no longer authenticate, download, or install content such as AntiVirus definitions or product updates.

To allow customers additional time to plan migrations, Symantec has introduced a workaround that allows LiveUpdate to continue to successfully authenticate valid content from Symantec through July 4, 2013.  This date may be extended if needed on a product-by-product basis.

For details, read the full knowledge base article.