DMN16 — Lexical representation of time string has ambiguous definitions

A lexical time string is defined o page 131 by XML Schema Part 2 Datatypes (for local times and offset times) and by ISO 8601 with the extended form of a local time (for zoned times).

Unfortunately XML Schema Part 2 and ISO 8601 has different definitions. Therefore it is unclear which of them to use. Or are both of them valid?

Additionally the user should not have different lexical time string formats for a local time, an offset time or a zoned time.

The list of ambiguities:

• ISO 8601 allows a leading "T" character prefix. XML Schema Part 2 does not.
• ISO 8601 allows optional seconds. In XML Schema Part 2, the seconds are mandatory.
• ISO 8601 allows decimal fraction for seconds and minutes. XML Schema Part does not allow this.
• ISO 8601 allows 00:00:00 and 24:00:00 for midnight. XML Schema Part 2 only allows 00:00:00.
• ISO 8601 allows time offset of hours only. Minutes are optional. XML Schema Part 2 always requires minutes.

Therefore clarification is needed. Which definitions are valid for FEEL? The stricter XML Schema Part 2 or the more user friendly ISO 8601 spec?

Deprecate IANA time zone use in time strings

• Remove the XML Schema Part 2 from the specification as the ISO 8601 covers it.
• Deprecate usage of IANA IDs for time literals
• Add new function to allow migration of deprecated use cases.