diff --git a/schema/idea.schema b/schema/idea.schema
index 386b394af018e423bcf6575d7b0a9e98c2e8cc3c..000e243de21c3e96045d2eb5aeb7218191db0f75 100644
--- a/schema/idea.schema
+++ b/schema/idea.schema
@@ -51,7 +51,6 @@
         "Duration": {
             "description": "String, containing time offset, intended for representing difference between two timestamps. Format is time part of [[http://tools.ietf.org/html/rfc3339|RFC 3339]], optionally prepended by \"D\" or \"d\" separator and number of days (which can have arbitrary number number of digits). \"D\" separator has been chosen to distinguish from internet time, and as a memory aid for \"duration\" or \"days\". For example \"536D10:20:30.5\" means 536 days, 10 hours, 20 seconds, 30.5 seconds, whereas 00:05:00 represents five minutes.\n\n[[http://tools.ietf.org/html/rfc2234|ABNF]] syntax:\n{{{\ntime-hour       = 2DIGIT  ; 00-23\ntime-minute     = 2DIGIT  ; 00-59\ntime-second     = 2DIGIT  ; 00-59\ntime-secfrac    = \".\" 1*DIGIT\nseparator       = \"D\" / \"d\"\ndays            = 1*DIGIT\n\nduration        = [days separator] time-hour \":\" time-minute \":\" time-second [time-secfrac]\n}}}",
             "type": "string",
-            "format": "date-time",
             "pattern": "^(?:[0-9]+[Dd])?[0-9]{2}:[0-9]{2}:[0-9]{2}(?:\\.[0-9]+)?$"
         },
         "URI": {