software updates

Since updating to Mavericks I cannot download software application updates to applications that were installed before the upgrade to Mavericks. Specific examples being Adobe, and Trusteer Rapport. I get the message:- " (application download name) can't be opened because it was not downloaded from the Mac App store". Can Apple do this ? Is it legal here in UK ??!! ....... it's very, very annoying that I cannot update my software when notified by vendors, and I can't even update from APP Store because the applications don't exist in there !!!!! Anyone else getting rather annoyed with Apple ?!