# How often do phone numbering plans change? 2019–2026 data

> We counted 182 phone-metadata releases from 2019 to 2026: a median of 14 days apart, and 230 of 245 regions changed. Why validation goes stale.

Canonical: https://mobilevalidate.com/blog/numbering-plans-change-research-2026 · Last updated: 2026-09-25

![Cover: How often do phone numbering plans change? 2019–2026 data](https://mobilevalidate.com/og/blog/numbering-plans-change-research-2026.png)


By MobileValidate team (https://mobilevalidate.com/about) · Published: 2026-09-25 · Category: Research · Tags: Numbering plans, Phone validation, E.164, Original research, Developers, Data quality

Phone numbering rules change about every two weeks. We counted 182 metadata releases of the open-source libphonenumber library between January 2019 and 23 September 2026. The median gap between releases was 14 days, and every release changed the rules of at least one region. 230 of the library's 245 regions changed at least once.

## What did we measure?

We measured how often the rules that decide whether a phone number is valid are updated. Those rules are the numbering plan of each country: which prefixes exist, how long numbers are, which ranges are mobile, fixed, toll-free or premium-rate.

Nobody publishes a single global log of numbering-plan changes. National regulators publish their own plans, and countries notify the International Telecommunication Union (ITU), which keeps a page per country ([ITU, 2026](https://www.itu.int/oth/T0202.aspx?parent=T0202)). Those notices come in many formats and languages.

So we used the best public proxy we know: the release notes of **libphonenumber**, the open-source library that many applications and ports use to parse and validate numbers. Every release lists the regions whose phone metadata changed, plus changes to carrier, geocoding and short-number data ([libphonenumber, 2026](https://github.com/google/libphonenumber/blob/master/release_notes.txt)). The notes are public under the Apache License 2.0, and they are consistent enough to count.

The full dataset is free to download: [numbering-plan changes 2019–2026](/datasets/numbering-plan-changes-2019-2026) (3,784 rows, CSV and JSON, CC BY 4.0).

## How often are numbering rules updated?

About twice a month, and very regularly. From 8 January 2019 (v8.10.3) to 23 September 2026 (v9.0.40) there were 182 releases. The median gap between two releases was 14 days, the mean 15.6 days. 80% of gaps were 16 days or shorter, and the longest was 35 days.

| Year | Releases | Distinct regions with phone-rule changes | Region updates (sum) | Carrier-data updates | Median days between releases |
|---|---:|---:|---:|---:|---:|
| 2019 | 23 | 178 | 351 | 128 | 14 |
| 2020 | 20 | 156 | 307 | 198 | 16 |
| 2021 | 25 | 108 | 234 | 123 | 14 |
| 2022 | 21 | 127 | 266 | 157 | 16 |
| 2023 | 24 | 123 | 271 | 141 | 14 |
| 2024 | 25 | 108 | 222 | 138 | 14 |
| 2025 | 25 | 98 | 206 | 162 | 14 |
| 2026 (to 23 Sep) | 19 | 114 | 198 | 149 | 14 |

"Region updates" counts each region once per release in which its phone metadata changed. A typical release changed the phone rules of 9 regions (median), and every one of the 182 releases changed at least one region. Some releases were far larger. v8.10.5 (6 February 2019) touched 107 regions, which looks like a broad clean-up rather than 107 national reforms.

The yearly pace is stable: 20 to 25 releases a year, an average of 23.3 for the full years 2019–2025. The number of distinct regions touched per year has fallen from 178 in 2019 to about 100–125 since 2021. That is consistent with the metadata catching up on older changes and then tracking new ones.

## Which regions change most often?

A handful of regions change much more often than the rest. Singapore's phone rules changed in 64 of the 182 releases, the United States' in 53 and Hong Kong's in 42.

| Region | Releases with phone-rule changes, 2019–2026 | Since 2024 |
|---|---:|---:|
| Singapore | 64 | 25 |
| United States | 53 | 23 |
| Hong Kong | 42 | 20 |
| Morocco | 38 | 9 |
| Israel | 35 | 17 |
| Georgia | 31 | 13 |
| Uganda | 30 | 19 |
| Western Sahara | 30 | 8 |
| United Kingdom | 28 | 4 |
| Australia | 25 | 7 |
| Tajikistan | 24 | 7 |
| Guyana | 23 | 19 |
| Cocos (Keeling) Islands | 23 | 6 |
| Christmas Island | 23 | 6 |
| Réunion | 22 | 5 |

Twenty-one regions had changes in every single year from 2019 to 2026, among them the United States, Germany, Japan, South Korea, Poland, Malaysia, Singapore and Hong Kong.

Two patterns explain much of the list:

- **Growing markets open new ranges.** Singapore and Hong Kong both use eight-digit national numbers and regularly open new blocks as demand grows. The United States adds area codes and overlays; each new code is a rule change for validation.
- **Shared country codes move together.** Morocco and Western Sahara share +212, and Australia, Cocos (Keeling) Islands and Christmas Island share +61. Réunion shares +262 with Mayotte. When one member of such a group changes, the others are often updated in the same release, so they appear together in the ranking.

## How much of the world changed?

Almost all of it. 230 of the 245 regions in the library's metadata ([libphonenumber, 2026](https://github.com/google/libphonenumber/blob/master/resources/PhoneNumberMetadata.xml)) had at least one phone-rule change between 2019 and September 2026. That is 94%. Since the start of 2023 alone, 186 regions (76%) changed at least once.

Among the 230 regions that changed, the median region changed in 7 releases over the period. 78 regions changed in at least six of the eight calendar years. Only 15 regions had no phone-rule change in the notes since 2019. They include small territories such as the Falkland Islands and Tokelau, but also countries such as Iraq, Cambodia and Serbia.

The ITU's own records show similar activity from the regulator side. On 25 September 2026 we read the posting date of the latest national numbering-plan document on each of the ITU's 239 country pages ([ITU, 2026](https://www.itu.int/oth/T0202.aspx?parent=T0202)). 83 of them (35%) were last posted in 2024, 2025 or 2026, including 40 in 2026 alone. At the other end, 69 pages still show a document from before 2016, so the ITU record is only as fresh as each country's notifications.

## What else changes besides validity rules?

Carrier and location data change even more often than validity rules. Between 2019 and September 2026 the release notes record 1,196 updates to carrier data across 213 country calling codes, and 302 updates to geocoding data across 167 codes.

| Change type (2019 to Sep 2026) | Updates | Distinct codes |
|---|---:|---:|
| Phone metadata (validity, number types, formats) | 2,055 region updates | 230 regions |
| Carrier data (original operator of a range) | 1,196 | 213 calling codes |
| Geocoding data (area names) | 302 | 167 calling codes |
| Short-number data (emergency, service codes) | 162 | 102 regions |
| Alternate formatting | 69 | 40 calling codes |

Carrier data in a library describes which operator a number range was **originally** assigned to. In countries with number portability, the operator that serves a number today can differ. That's the gap our post on [why carrier lookups can be wrong](/blog/mobile-number-portability-why-carrier-lookups-can-be-wrong) explains, and why a live [carrier lookup](/services/carrier-lookup) answers a different question than a prefix table.

## Why does this matter for phone validation?

Because a validation library is a snapshot of rules that keep moving. If your app bundles metadata and ships an update twice a year, it misses about a dozen releases in between. During that time:

- **New numbers fail validation.** A customer with a number from a newly opened range sees "invalid phone number" and may not come back.
- **Line types are wrong.** A new mobile range can be classified as unknown or fixed-line, which breaks rules like "send OTP only to mobile".
- **Carrier and region hints go stale.** Routing, fraud rules and analytics that use the original-carrier or area data drift over time.

Practical steps that follow from the data:

1. **Update validation metadata on a schedule.** A monthly dependency update keeps you within about two releases of the latest rules. Automate it the way you update security patches.
2. **Validate on the server, not only in the client.** Mobile apps and cached front-end bundles can lag for months. A server-side check can be updated in one deployment.
3. **Don't hard-reject on validity alone.** If a number fails a local check but looks plausible, accept it with a flag or ask for confirmation, and re-check it later.
4. **Separate format from reality.** A valid format doesn't mean the number is assigned, active or mobile. Our [E.164 guide](/blog/e164-phone-number-format-guide-for-developers) covers formatting; a live [check whether a number is active](/blog/how-to-check-if-a-phone-number-is-active) covers the rest.
5. **Re-check stored lists.** Numbers you validated years ago were checked against old rules. Our [bulk list-cleaning guide](/blog/how-to-clean-a-phone-number-list-in-bulk) shows a cadence.

MobileValidate normalizes every number to [E.164](/glossary/e164) on the server before any check, and marks numbers that fail the numbering-plan rules as `invalid_number`. Those aren't charged, and neither are other inconclusive results.

## How did we collect and count the data?

### Methodology

1. **Download.** We fetched `release_notes.txt` from the libphonenumber repository on 25 September 2026. The latest entry was v9.0.40, dated 23 September 2026.
2. **Parse.** We split the file into releases by their header line (date and version) and kept releases dated 1 January 2019 to 25 September 2026: 182 releases, from v8.10.3 to v9.0.40.
3. **Classify.** Each "Metadata changes" bullet was mapped to a change type: phone metadata, short-number metadata, carrier data, geocoding data or alternate formatting, each as "updated" or "new". Region lists (two-letter codes) and country-calling-code lists (for carrier, geocoding and formatting data) were split into one row per code, de-duplicated within a release.
4. **Count.** Releases per year, the gaps in days between consecutive release dates, distinct codes per year and per period, and releases per region.
5. **Denominator.** The 245 two-letter regions defined in `PhoneNumberMetadata.xml` on the same date (non-geographic calling codes excluded).
6. **Regulator cross-check.** For the ITU figure, we read the latest "Posted" date on each of the 239 country pages linked from the ITU national numbering plans index, with one request per page and a pause between requests.

The resulting rows are the [dataset](/datasets/numbering-plan-changes-2019-2026). Anyone can reproduce the counts from the public release notes with a short script.

### Limitations

- **One library is a proxy.** The release notes record what the library's maintainers changed, which usually follows a national decision with some delay. Some changes may be batched, split or never recorded.
- **A row isn't a size.** "Updated phone metadata for SG" can mean one new block of numbers or a large reform. We count occurrences, not the number of ranges affected.
- **Clean-ups inflate some releases.** Large releases such as v8.10.5 (107 regions) likely include corrections and consistency fixes, not only national changes.
- **Shared codes double-count.** Regions that share a calling code often change together, so their counts are not independent.
- **ITU dates are posting dates.** A page's latest date can reflect a re-posted document. Several pages share the same 2026 date, which suggests batch publication.
- **2026 is partial.** It covers 1 January to 23 September.

## What are the key takeaways?

- Phone numbering rules are updated about every two weeks: 182 releases from 2019 to September 2026, with a median gap of 14 days.
- 94% of regions (230 of 245) had at least one rule change in that period, and 76% changed since 2023.
- Singapore, the United States and Hong Kong change most often. New ranges and new area codes drive much of the churn.
- Carrier data changes often too (1,196 updates across 213 calling codes), and prefix-based carrier data can't reflect ported numbers.
- Update validation metadata monthly, validate on the server, and don't hard-reject numbers on a stale local check.
- The dataset behind this post is free to reuse: [numbering-plan changes 2019–2026](/datasets/numbering-plan-changes-2019-2026). We plan to refresh it periodically and will state the new date range each time.

## Sources

1. [libphonenumber release_notes.txt (v8.10.3 to v9.0.40)](https://github.com/google/libphonenumber/blob/master/release_notes.txt) — libphonenumber project, 2026
2. [libphonenumber PhoneNumberMetadata.xml](https://github.com/google/libphonenumber/blob/master/resources/PhoneNumberMetadata.xml) — libphonenumber project, 2026
3. [National Numbering Plans](https://www.itu.int/oth/T0202.aspx?parent=T0202) — International Telecommunication Union (ITU-T), 2026
4. [Recommendation ITU-T E.164: The international public telecommunication numbering plan](https://www.itu.int/rec/T-REC-E.164) — International Telecommunication Union, 2010

## Frequently asked questions

### How often do phone number formats change?

Often. The widely used open-source libphonenumber library published 182 metadata releases between January 2019 and 23 September 2026, a median of 14 days apart. Every one of them changed the phone-number rules of at least one region, and a typical release touched 9 regions.

### Which countries change their numbering plans most?

In release notes from 2019 to September 2026, Singapore's rules were updated in 64 releases, the United States' in 53 and Hong Kong's in 42, followed by Morocco (38), Israel (35) and Georgia (31). Frequent updates usually mean new number ranges are being opened, not that the whole plan is redesigned.

### Why does a phone validation library go stale?

Because its metadata is a snapshot. When a regulator opens a new mobile range or area code, numbers in that range fail validation until the application ships a newer version of the metadata. With a release every two weeks, a library that is a year old has missed about 24 updates.

### Can I download the data behind this analysis?

Yes. The dataset lists every region and country calling code named in the release notes, with the date, version and change type. It's free to reuse under CC BY 4.0 at /datasets/numbering-plan-changes-2019-2026.

### Does this measure every numbering change in the world?

No. It measures what one widely used library recorded. Some national changes are published by regulators before or without a library update, and one release note line can cover a small range or a large reform. Treat the counts as a lower-bound signal of churn.