7 Reading a 3GPP number — the series, the version, the file name

7.1 Why the number carries the status

3GPP documents have no "draft" watermark and no traffic-light. What they have is a number, and that number is expected to answer three questions at once: what kind of document is this, how far has it got, and which Release does it belong to.

Read it wrongly and you can quote a draft at a supplier, or build against a Release your customer never bought. The rules are short, and worth knowing by heart.

7.2 The specification number: aa.bbb

Every document is 3GPP TS aa.bbb or 3GPP TR aa.bbb §4.0. Two fields, and both are chosen according to what the document is rather than when it was written.

The first field says the subject. The document is emphatic that this table shall be strictly enforced, while the second table is guidance from which it is acceptable to deviate for backwards compatibility §4.0. The ranges for the current numbering are:

Range	What lives there
21	requirements specifications
22	service aspects — stage 1
23	technical realization — mainly stage 2
24	signalling protocols between device and core network
25	radio access aspects
26	codecs
27	data
28	signalling protocols between radio subsystem and core network
29	core network signalling protocols
30	programme management
31	SIM and UIM
32	charging, operations, administration and maintenance
33	security aspects
34	test specifications
35	algorithms
36	evolved radio access — introduced in Release 8
37	aspects spanning several radio technologies
38	5G "New Radio" — first studies in Release 14

The second field carries a quieter distinction that saves a great deal of time §4.0:

• aa.8bb — Technical Reports not intended for publication: working documents of 3GPP groups, which the partners will not transpose into their own standards.

• aa.9bb — Technical Reports that are intended for publication.

So a report number tells you whether anybody outside was ever meant to read it.

7.3 The three version digits

The Foreword of every 3GPP document states the rule, in the same words each time.

Clause 4.0A fills the rest in with table 3 §4.0A:

• V1. The first digit — major, also called the release. 0 is a draft. 1 means presented to the plenary for information, with the responsible group estimating the document at least 60% stable. 2 means presented for approval, at an estimated 80%. 3 or greater means approved and under change control, and the value is then the Release.

• V2. The second digit — technical. Incremented every time a technical change goes in. Once the document is under change control, that only happens when the plenary approves one or more change requests. Reset to zero whenever the first digit changes.

• V3. The third digit — editorial. Incremented when a purely editorial change goes in. Reset to zero whenever the second digit is incremented or reset.

The percentages are guidelines and the document says so out loud: the figures are obviously subjective and the decision is ultimately the responsible group's §4.0A. What is not negotiable is that a document reaching that point and going to the plenary for the first time carries major version 1 §4.0A.

The first digit therefore changes meaning halfway through a document's life. Up to 2.y.z it is a maturity marker. From x.0.0 onwards it is a Release number §4.0B, and the document's maturity is no longer expressed by the version at all — it is expressed by whether the Release is frozen or closed What a Release is, and what freezing one costs.

That switch is why the jump exists. A document approved for Release 4 goes from 2.0.0 to 4.0.0, with no 3.y.z in between §4.1.1.

7.4 What a version number implies about the past

Clause 4.4 turns the same rules around and asks, for each shape of version number, what must already have happened §4.4. It is the clause to open when somebody hands you a number and you need to know what you are holding.

Version	What it implies
0.x.y	draft, internal; never yet presented for information
1.0.0	draft, internal; this version is being presented for information
1.x.y	draft; an earlier 1.0.0 went for information
2.0.0	draft, internal; this version is being presented for approval
2.x.y	draft; an earlier 2.0.0 was presented and not approved
x.y.z, x ≥ 3	under TSG change control or closed

Clause 4.3 says the same thing about a major version rather than an individual version: 0, 1 and 2 are draft or withdrawn and internal to the TSG; anything above 2 is under Working Group change control, under TSG change control, closed or withdrawn, and is either authorised for publication or internal; and a major version under TSG change control is either frozen or not yet frozen §4.3.

A version under Working Group change control is always TSG internal §4.3. That is a real state, not a formality: the Working Group is agreeing changes, but the plenary has not yet approved them, so the text exists in a form nobody outside should be building from.

7.5 Both numbers, packed into a file name

Clause 5A packs the specification number and the version into one string §5A:

aabbb-xyz.eee

aa and bbb are the two halves of the specification number, x, y and z are the three version digits, and eee is the file extension of whatever tool produced it. Source files are stored compressed, with the same name and the extension .zip.

The version characters are base-36 digits: 0 to 9 then a to z, so 10 is a and 35 is z §5A. That works until a version element passes 35, at which point the whole file name switches to two decimal characters per element — version 15.35.0 of TS 29.341 is 29341-fz0, and 15.36.0 is 29341-153600 §5A.

Multi-part documents insert the part number, aabbb-n-xyz.eee, and part numbers are always decimal, never letters §5A. A document split across several source files appends a file identifier in brackets §5A.

One convention is worth memorising because it prevents an expensive mistake. Draft versions may be made available in a group's own directory, and are distinguished by substituting d for the hyphen — 28033d410.zip. Such files shall never appear in the official specification directories §5A.

7.6 Where this leads

The number now reads. How a 3GPP meeting decides, and the word it decides in covers the vocabulary of the decision that moved it, and Reading either body's paper trail from a cold start uses all of this to trace one sentence back to the meeting that put it there.