How to know exactly the year of release of the Xiaomi phone by serial number: code decryption and alternative methods

Why it’s important to know the year of Xiaomi’s smartphone launch and where to look for a serial number

Buying a used Xiaomi smartphone is always fraught with risks: the seller can hide the real age of the device, and the appearance does not always betray the true “fatigue” of the battery or components. Year of release is a key parameter that affects the cost, battery life and even compatibility with the latest firmware versions. For example, the 2019 Redmi Note 8 models no longer receive official MIUI updates, while the 2020 devices are still supported.

The serial number (S/N) is a unique identifier that Xiaomi assigns to each device during the manufacturing phase, which contains encrypted information about the assembly date, the manufacturer and even the batch of components. Unlike IMEI, which can be forged or reset, the serial number is rigidly tied to hardware and does not change throughout the life cycle of the gadget.

• 📱 On the back of the box (under or next to the barcode).
• 🔍 In the phone settings: Settings → The phone. → General information → Serial number.
• 🔋 Under the battery (for models with a removable lid, for example, Redmi) 4A).
• 🖥️ Through computer: connect your phone in Fastboot mode and type in the command fastboot getvar sn

It is important to understand that Xiaomi uses several serial number formats depending on the year of release and model, for example, for older devices (before 2018), the date was encrypted openly, and in new ones it was encrypted in alphanumeric format. Next, we will discuss all the current methods of decryption, including a unique algorithm for models of 2021-2026, which is not dokumented in official sources.

Method 1: Decoding the Xiaomi serial number in a standard format (2015–2020)

Until 2021, Xiaomi used a relatively simple date encoding scheme in the serial number.

[The letter prefix][Year][Month][Day][Unique Identifier]

Where:

• 🔤 Letter prefix (2-3 characters) – the code of the plant or series (for example, HM for Redmi, MI for Mi).
• 📅 Year - last digit of the year (for example, 9 = 2019).
• 📆 Month and day: two digits of the month and two digits of the day (e.g, 0512 = 12 may).

Example: The serial number HM90512XXXXXX stands for:

• 📌 HM — Redmi series.
• 📌 9 - 2019.
• 📌 0512 - 12 May.

But there are nuances:

⚠️ Note: Some Xiaomi models (e.g. Poco) F1 or Mi Mix 2S) They used an alternative format where the year was encoded in two digits (e.g. 19 instead of 9). If the prefix is followed by the letter prefix 18, 19 or 20, this indicates a full year (2018, 2019, 2020, respectively).

Find S/N on the box or in the settings

Select 4-6 characters after the letter prefix

Compare the figures with the table above

Check the logicality of the date (for example, February 31 does not exist)-->

Method 2: New serial number format (2021–2026) – decryption algorithm

Starting in 2021, Xiaomi moved to a more complex coding system, where the release date is not directly displayed, instead using a combination of letters and numbers that requires additional calculations.

][Prefix of the model][Factory code][Date code (4 characters)][Unique ID]

The key is the date code, which is one letter and three digits (e.g. A365 or D120).

1. The letter corresponds to the year in the table:

The remaining three digits represent the day of the year (from 001 to 365). B200 signifier:

• 📅 B → 2022.
• 📆 200 → 200th day of the year (July 19).

For convenience, you can use an online calendar of days to convert the day number to the date.

⚠️ Note: In 2023, Xiaomi began using two letters to code the year (e.g., the year, AA, AB). It's about running out of single-letter combinations. AA123, This is probably a model from 2023 to 2026, but the exact decoding requires a call for support.

💡

If the serial number begins with M2102, M2203 or the like, the first two digits after M often indicate a year (2021, 2022, respectively).

Method 3: Determination of IMEI Release Year (Alternative Method)

If the serial number is erased or unavailable, you can try using IMEI, the international mobile device identifier, but there is an important limitation: the IMEI itself does not contain a release date, but it can be used for verification through Xiaomi databases or third-party services.

Steps:

1. Find it. IMEI: 📞 Dial *#06# - the number will appear on the screen. 📦 Look at the sticker under the battery or on the box.
2. Check IMEI through Xiaomi’s official service: Go to the checkout page. Enter IMEI and captcha. The results will indicate the activation date (not to be confused with the production date!).

• 🌍 IMEI.info (paid check).
• 🔍 SNDeeP (for Chinese models).

Important: The activation date may differ from the production date by several months (depending on logistics and sales time).For example, the Xiaomi Mi 11, released in December 2020, could not be activated until January 2021.

How to verify the authenticity of a serial number and avoid forgery

Fraudsters often fake serial numbers on boxes or stickers to pass off an old device as a new one.

1. Compare. S/N three-place: 📦 On the box. 📱 In the phone settings (Settings) → The phone). 🔋 Under the battery (if possible) If the numbers don't match, you're looking at a fake or a replacement replacement device after repair.
2. Check the format: 🔍 Xiaomi serial number always consists of 14-16 characters (letters). + figure). 🚫 If you only see numbers or code that is too short (e.g. 123456) it is a fake.

Use the official service:

• 🌐 Go to the Xiaomi checkout page.
• 📋 Enter the serial number and IMEI.
• ✅ If the system shows the model and activation date, the number is authentic.

Be especially careful about devices from Chinese markets (e.g. Xiaomi China ROM) and their serial numbers may not be validated in a global database, but this does not always mean fakes, just for the domestic Chinese market.

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If the serial number starts with 000, 111 or repeating characters, it is 100% fake. Xiaomi's original numbers never contain such combinations.

Table of conformity of years of release and models of Xiaomi (2018-2026)

For convenience, we have collected data on popular models and their typical years of release. Note that the same model could be produced in different factories in different years (for example, the Redmi Note 9 was produced from 2020 to 2021).

If your model is not listed in the table, try to find it on GSMArena – it often shows the exact dates of the announcement and the start of sales, which will help to match with the serial number.

What to do if the serial number is not decrypted?

If you are faced with a non-standard serial number format or can not determine the year of release, try the following steps:

1. Contact us for support of Xiaomi: 📧 Write to Twitter or Facebook with a photo of the serial number. 📞 Call the hotline (for Russia: 8 800 700 02 25) In the answer, enter the model and the full serial number - specialists will provide official information.
2. Check the date of battery production: 🔋 Most Xiaomi batteries have a date code in the format YYYY-MM-DD or WWYY (week-year). 🛠️ Disassembly may be required to access the battery (not recommended without experience!).

Use the diagnostic applications:

• 📱 Install. CPU-Z or AnTuTu.
• 🔍 In the "Device" or "System" section, the firmware assembly date may be displayed (not to be confused with the production date!).

⚠️ Note: If the seller refuses to provide a serial number or IMEI It's a good idea to be alerted before you buy it, maybe it's wanted, locked, or has an unofficial firmware.

FAQ: Frequent questions about Xiaomi serial numbers