I'd say that's almost certainly hosts.cfg. But look for "delayred" in the manual and see where that is supposed to go. Then you'll know.

From: Cure4All [mailto:cure4all at gmail.com] Sent: Friday, September 27, 2013 08:04 PM To: xymon at xymon.com <xymon at xymon.com> Subject: [Xymon] Xymonnet bad tags

Hello, I need help to find which file do I need to edit in order to fix this Warning. Nothing else shows up in the logs. Thank you.

WARNING: The 'bad<TESTNAME>' syntax has been deprecated, please convert to 'delayred' and/or 'delayyellow' tags