School of Specs CT1 — the group that writes what your…Quick start

How the work moves, and how to follow it · chapter 3 of 4 · 4 minutes

3 How something gets into a specification

The change request, the meeting that decides it and the version number that comes out — with the real numbers from one meeting, C1-161.

Built from §Foreword

3.1 Nobody rewrites a specification

Once a 3GPP document is approved it is under change control, and its own foreword says what that means: it is re-released with a higher version number whenever it is modified §Foreword.

TSG is the document's own shorthand for the body that approves it and releases the new version; the foreword never spells the three letters out, which is a habit worth getting used to.

So nobody edits a specification. Instead they write a change request — a CR: one document, one problem, one set of replacement paragraphs, filed against one published specification. It is the unit of work in CT1.

4235 CT1 documents arrived in the twelve months to 2026-08-04 [1], and 2835 of them were change requests [2]. A pCR is the same idea aimed at a document still being drafted rather than one already published, and 563 of those came in the same year [3].

Which specification takes that traffic shifts with the years. In the last twelve months TS 24.301 drew 499 change documents [4], and TS 24.369 — Ambient IoT, a document nobody was writing a few years ago — drew 430 [5].

3.2 One real change request

That is the whole shape of the thing. A named filer, a named specification, a title that says what is wrong, a number that identifies the change inside that specification, and a category letter. The record does not say what the categories mean, and it does not say which paragraph the change replaced.

Six more agreed change requests from that meeting are in this course's source list, one for each of the specifications C1-161 changed most, and every one of the seven carries the word "correction" in its title. Seven is not enough to tell you what all 2835 of the year look like.

3.3 The meeting is where it is settled

172 CT1 meetings had started by 2026-08-04 [6], and the next ones are already in the calendar.

The last six held and the next three planned all run Monday to Friday. C1-161 sat in Dalian from 2026-05-18 to 2026-05-22, and C1-162 is planned for Prague from 2026-08-24 to 2026-08-28.

617 documents were put to C1-161 [7], and its report — still a draft [8] — gives every one of them an outcome word:

Outcome Documents
revised 259 [9]
agreed 174 [10]
postponed 70 [11]
noted 53 [12]
merged 33 [13]
withdrawn 19 [14]

Those six do not add up to 617. Two further outcome words, "approved" and "endorsed", appear in the data with no count behind them, so the missing documents cannot be worked out by subtraction.

3.4 New work opens with a document of its own

A WID is a work item description, the paper that opens a named piece of work; a SID opens a study instead. Nine new or revised work items were agreed at C1-161 [15].

One of the nine opened a second phase of work on Ambient power-enabled Internet of Things, filed by Huawei, HiSilicon C1-262440; another opened a study on emergency call robustness, filed by Google C1-262596.

Work items are how the paper is sorted: 219 of them received a CT1 document during the year [16], the busiest being AmbientIoT-CT with 420 [17]. Those names are stored exactly as the documents spell them, and nothing in the record says what they stand for.

Where the numbers in this chapter come from

  1. 4235 CT1 documents in the twelve months to 2026-08-04 rows in the pygppe document database, table tdoc where meeting starts with 'C1-' and uploaded >= '2025-08-04', read 2026-08-04
  2. 2835 CT1 documents of kind 'CR' uploaded on or after 2025-08-04 rows in the pygppe document database, table tdoc where meeting starts with 'C1-' and tdoctype='CR' and uploaded >= '2025-08-04', read 2026-08-04
  3. 563 CT1 documents of kind 'pCR' uploaded on or after 2025-08-04 rows in the pygppe document database, table tdoc where meeting starts with 'C1-' and tdoctype='pCR' and uploaded >= '2025-08-04', read 2026-08-04
  4. 499 CT1 documents change 24.301 (Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3), in the twelve months to 2026-08-04 rows in the pygppe document database, table tdoc where meeting starts with 'C1-' and crspec='24.301' and uploaded >= '2025-08-04'; rank 1 of the whole group, read 2026-08-04
  5. 430 CT1 documents change 24.369 (Ambient IoT Non-Access-Stratum (AIoT NAS) protocol for 5G System (5GS); Stage 3), in the twelve months to 2026-08-04 rows in the pygppe document database, table tdoc where meeting starts with 'C1-' and crspec='24.369' and uploaded >= '2025-08-04'; rank 3 of the whole group, read 2026-08-04
  6. 172 CT1 meetings had started by 2026-08-04 rows in the pygppe meetings database, table meetings where tb='3GPP CT 1' and start_day <= '2026-08-04', read 2026-08-04
  7. 617 documents were put to C1-161 rows in the pygppe document database, table tdoc where meeting='C1-161', read 2026-08-04
  8. CT1 meeting report C1-161 the Markdown conversion pygppe keeps at /var/www/whatthespec.net/data/data/meetings/ftp.3gpp.org/tsg_ct/WG1_mm-cc-sm_ex-CN1/TSGC1_161_Dalian/Report/Draft_CT1_161_meeting_report_v100/Draft_CT1_161_meeting_report_v100.md, read 2026-08-04
  9. 259 documents came out of C1-161 as 'revised' rows in the pygppe document database, table tdoc where meeting='C1-161' and status='revised', read 2026-08-04
  10. 174 documents were agreed at C1-161 rows in the pygppe document database, table tdoc where meeting='C1-161' and status='agreed', read 2026-08-04
  11. 70 documents came out of C1-161 as 'postponed' rows in the pygppe document database, table tdoc where meeting='C1-161' and status='postponed', read 2026-08-04
  12. 53 documents came out of C1-161 as 'noted' rows in the pygppe document database, table tdoc where meeting='C1-161' and status='noted', read 2026-08-04
  13. 33 documents came out of C1-161 as 'merged' rows in the pygppe document database, table tdoc where meeting='C1-161' and status='merged', read 2026-08-04
  14. 19 documents came out of C1-161 as 'withdrawn' rows in the pygppe document database, table tdoc where meeting='C1-161' and status='withdrawn', read 2026-08-04
  15. 9 new or revised work items were agreed at C1-161 rows of Annex D (List of agreed/approved new and revised Work Items) in the draft meeting report at /var/www/whatthespec.net/data/data/meetings/ftp.3gpp.org/tsg_ct/WG1_mm-cc-sm_ex-CN1/TSGC1_161_Dalian/Report/Draft_CT1_161_meeting_report_v100/Draft_CT1_161_meeting_report_v100.md, counted 2026-08-04
  16. 219 named work items received CT1 documents in the twelve months to 2026-08-04 distinct winame in the pygppe document database, table tdoc where meeting starts with 'C1-' and uploaded >= '2025-08-04', read 2026-08-04
  17. 420 CT1 documents for the work item AmbientIoT-CT in the twelve months to 2026-08-04 rows in the pygppe document database, table tdoc where meeting starts with 'C1-', uploaded >= '2025-08-04' and winame='AmbientIoT-CT'; rank 1 of 6, read 2026-08-04

Every source this course is built on

Check yourself

Answers appear when you pick one, with where they come from.

Q3.1 How many of the 4235 CT1 documents of the last twelve months were change requests?

Q3.2 In a version number x.y.z, what makes the second digit go up?

Q3.3 What was the most common outcome for the 617 documents put to meeting C1-161?

Q3.4 How many new or revised work items were agreed at C1-161?

This chapter was written against TS 24.501 version 20.0.0, and built from a source register generated 2026-08-04. A newer version of the document may say something else.