How to know how old Xiaomi phone is: from serial number to hidden menus

You bought Xiaomi off your hands or found an old smartphone in your desk drawer — and now you want to know its real age? The age of the phone affects resale value, the duration of update support, and even the risk of sudden breakdowns. For example, lithium-ion batteries lose up to 20% of their capacity after 2 years of active use, and models older than 3 years often lose official firmware.

In this article, 7 working ways to determine Xiaomi’s release year, from the obvious (check box) to the hidden (engineering codes and service menus), we’ll look at how to decipher the serial number, where to look for a production date in MIUI, and why data from different sources may not match. And also, a table of serial number and year matching for popular Redmi, POCO and Mi models.

1. Checking the box and documents

The easiest way to view the original packaging is to see the original packaging. On Xiaomi boxes (especially those released before 2021), the production date is often listed in YYYY-MM-DD or YY/MM format on:

• 📦 Serial number sticker (usually at the bottom of the box) MFD (Manufacture Date) or DATE.
• 🏷️ Warranty card – if the phone was purchased officially, there may be a date of sale (not to be confused with the date of production!).
• 📄 Check or invoice - in the documents from the store sometimes duplicate information about the party.

⚠️ Note: On the boxes of new models (for example, Xiaomi 13 or Redmi Note 12), the date of production is often not indicated - instead, only the serial number is put.

2. Decoding of the serial number (S/N)

The serial number (S/N) is a unique device identifier that contains encrypted release date information. Xiaomi's serial format depends on the year of production:

🔍 Where to find the serial number?

• 📱 On the phone: Settings → The phone. → General information → Serial number.
• 🔋 Under the battery (on older models with a removable lid, for example, Redmi). 4A).
• 🖱️ In Fastboot mode: Turn off the phone, press Volume down + Power, connect to the PC and type the command: fastboot getvar serialno

💡

If the serial number starts with the letters MZD, LZD or KZD, the device is assembled in a factory in India, and these phones are often numbered separately — check IMEI for the exact date.

3. IMEI Verification: Online Services and Decryption

IMEI (International Mobile Equipment Identity) is another unique identifier that can be used to determine age. Unlike the serial number, the IMEI does not always contain a direct date of production, but allows you to know the month and year of activation through official databases.

📌 How do you know? IMEI?

• 📞 Dial on the phone keyboard *#06# - a window with a 15-digit code will appear.
• 📱 In settings: About the phone → General information → IMEI.
• 🔋 Under the battery (on models with a removable cover).

🔎 How to check IMEI online?

1. Go to IMEI.info or SNDeeP.
2. Enter the IMEI in the verification field.
3. In the results, look for Date of Manufacture or Approx. Age.

⚠️ Note: Some services (for example, IMEI24) This may show the wrong year for the Chinese versions of Xiaomi (with the C suffix in the model, for example, the Redmi Note 10 Pro C.

4. Hidden menus of engineering mode

Xiaomi phones have hidden service menus where you can find information about the date of production, these menus are not intended for ordinary users, but access to them does not require root rights.

🔧 Instructions for most models:

1. Open the Phone app.
2. Enter the combination: ##4636##
3. Go to the Device Information tab.
4. Look for Manufacture Date or Hardware Info.

📌 Alternative codes for new models:

• #284## - Equipment test (on some POCO displays the date of assembly).
• ##6484## is the MTK Engineer Mode menu (for MediaTek-based phones).
• ##36446337## - information about the firmware version and build date.

⚠️ Attention: On phones with MIUI 14+ Some engineering codes may be blocked. If nothing happens after you enter the combination, try typing it without the characters and # (e.g. 4636 instead of #4636##*).

5. Verification through MIUI and system files

The MIUI operating system stores the date of first activation and firmware assembly, which is not always the same as the actual age of the phone, but can serve as an additional source.

🔍 Where to find?

1. Open the settings → About the phone → version of MIUI.
2. Click on the MIUI version several times until the words “You are a developer” appear.
3. Back to Settings → Additionally. → For developers.
4. Find the Build Date, which is the firmware compilation date, which is usually close to the device release date.

📁 Checking system files (for advanced users):

• Install a file manager with access to root folders (such as MiXplorer).
• Go to /system/build.prop.
• Find the lines: ro.build.date.utc= ro.boot.ddr_info= The first line contains the firmware build date in Unix-time format (can be converted here).

💡

The firmware build date may be 1 to 3 months later than the actual production date, which is normal. Compare it to the serial number for accuracy.

Age determination by model and characteristics

If none of the above methods worked, you can roughly determine the age of the phone by its model and specifications.

1. Find out the exact phone model in Settings → About Phone → Model (e.g. M2007J3SC for Redmi Note 9 Pro).
2. Check the date of the announcement of the model on official resources: 🌍 Xiaomi official website (products section). 📱 MIUI News - history of updates. 📈 GSMArena – Technical Specifications.

💡 Tip: If the phone model ends in G (e.g. Redmi) 9A G, a global version released later than the Chinese version, can be 2-6 months younger than the original version.

7 Physical signs of wear: what gives the age of the phone

Even without technical data, you can estimate the age of Xiaomi by external signs.

• 🔋 Battery: If the phone is discharged in 3-4 hours with moderate use - it is 2+ Bloated battery (body "open") - sign of age 3+ years.
• 📱 Body and screen: Yellow display (especially on a white background) - characteristic of AMOLED-Screens older than 2019: erased labels on buttons or logos are a sign of active use of 1.5-2 years.
• 🔌 Charging port: Shattered USB-C Or Micro-USB (cable drops out) -- typical of phones older than 2018. Contact oxidation (green coating) -- the device was operated in a wet environment.

⚠️ Note: On some models (e.g, POCO X3 NFC) After 2 years of operation, the module begins to fall off. NFC — It's related to the wear of the antenna. NFC It stopped working for no apparent reason, and the phone is likely to be released before 2021.

FAQ: Frequent questions about the age of Xiaomi phones