Tracks field optionality changes between HL7 v2.x versions.
Currently tracks v2.7+ field deprecations (fields that became B — backward
compatibility only — in v2.7). When validating a message at v2.7 or later,
these fields should NOT be enforced as required even though the baseline
v2.5.1 schema marks them :r or :c.
HL7 does not change a field's optionality from :o → :r between versions.
What it does is retire previously required/conditional fields by marking them
:b (backward compatibility only) and introducing replacement fields. The
HL7v2.Validation.FieldRules pipeline uses
exempt?/3 to skip required-field enforcement for known deprecations when a
message declares itself at a version where the field is no longer required.
Currently tracked v2.7 deprecations
PID-13,PID-14— telecom fields, replaced byPID-40(patient_telecommunication_information).OBR-10,OBR-16— collector/ordering provider, replaced by thePRTsegment (andOBR-50for parent service identifier).ORC-10,ORC-12— entered_by / ordering_provider, replaced by thePRTsegment.
Note: the baseline v2.5.1 schema shipped with this library currently marks
several of these deprecated fields as :o already, so the exemption is a
no-op for them today. The deprecation list is still enforced so that any
future schema tightening (e.g., reinstating the canonical v2.5.1 :r/:c
markings for OBR-10/OBR-16) remains safe for v2.7+ messages without
additional bookkeeping.
Summary
Functions
Returns true if a field is exempt from required-field enforcement at the
given version, and false if the field should still be required per the
baseline v2.5.1 schema.
Returns all v2.7 deprecations as a list of {segment_id, field_seq} tuples.
Functions
@spec exempt?(binary(), pos_integer(), binary() | nil) :: boolean()
Returns true if a field is exempt from required-field enforcement at the
given version, and false if the field should still be required per the
baseline v2.5.1 schema.
The version argument should be a normalized HL7 version string (e.g.
"2.5.1", "2.7"). Pass nil when the validating caller has no version
context — the function returns false in that case and the baseline
v2.5.1 rules apply unchanged.
Examples
iex> HL7v2.Standard.VersionDeltas.exempt?("PID", 13, "2.7")
true
iex> HL7v2.Standard.VersionDeltas.exempt?("PID", 13, "2.8")
true
iex> HL7v2.Standard.VersionDeltas.exempt?("PID", 13, "2.5.1")
false
iex> HL7v2.Standard.VersionDeltas.exempt?("PID", 5, "2.7")
false
iex> HL7v2.Standard.VersionDeltas.exempt?("PID", 13, nil)
false@spec v27_deprecations() :: [{binary(), pos_integer()}]
Returns all v2.7 deprecations as a list of {segment_id, field_seq} tuples.
Useful for documentation, introspection, and tests that want to assert the exhaustive deprecation set without duplicating the literal.