Owners of Xiaomi, Redmi and Poco smartphones often face a strange situation: you write a normal text message, and in the delivery status suddenly appears the icon of the envelope with a picture or status changes to “Multimedia”. This is not just a visual effect, it is a signal that the data protocol has changed from SMS to MMS. For the user, this can mean unnecessary costs if the Internet packet is not connected, or delays in delivering messages to contacts.
The fundamental difference between these formats lies in the transmission technologies. Conventional SMS (Short Message Service) works through signal channels of the cellular network, without requiring an Internet connection and with strict data limits. At the same time, MMS (Multimedia Messaging Service) uses data channels (GPRS/3G/4G/5G) to send not only text but also attachments. Android system based on the shell MIUI or HyperOS automatically switches modes if it detects conditions that are incompatible with the short message standard.
Understanding why this switching happens is critical to saving budget and keeping privacy. Often users don’t even notice they’ve sent a “heavy” message until they receive an invoice from the operator or see an icon on the screen. In this article, we’ll go into detail about the technical reasons for converting, setting up messengers, and how to force them to return to the classic text format.
Technical limitations of SMS format and automatic conversion
The main reason your message becomes multimedia is because it exceeds the character limit. The standard GSM protocol on which cellular communication is based was originally designed to transmit short service notifications and texts. The basic limit is 160 characters for Latin and numerals. However, once you use Cyrillic, Russian alphabet or special characters, the encoding changes to UCS-2, and the limit drops to 70 characters per message.
Modern Xiaomi smartphones can glue long messages together, breaking them apart and putting them back together on the recipient’s phone. But if the text gets too voluminous or contains specific control characters, the Android operating system may decide to send it as a single block of data via MMS to ensure delivery is unaltered, especially when sending messages to short numbers of services or banks.
⚠️ Attention: When sending MMS If you don't have a data plan with a traffic packet, one such message can cost significantly more than a regular one. SMS.
It is also worth considering that some carriers have their own limitations on the length of the chain. SMS. If you write a blank text on multiple screens, your phone may find it ineffective to break it down into 10 parts, and it’s easier to send one. MMS-In the message settings. MIUI Sometimes you can find the option to limit the length, but most often the system makes this decision autonomously, based on algorithms for saving network resources.
The influence of emojis, stickers and text formatting
One of the most common and subtle reasons for conversion is the use of emojis. Although modern smartphones display smaliki as part of text, technically many of them (especially composite or newer versions of emojis) can take up more bytes than a regular character. When you add several of these elements to a message, the total weight of a message in bytes can exceed the threshold, forcing the Xiaomi phone to switch to MMS protocol.
In addition, messaging apps preinstalled on Redmi and Poco often support rich text formatting.If you use bold, italic, underline or change the color of text (a feature available in some themes and launchers), the message ceases to be "clean» ASCII It's abuzz with formatting metadata that's standard. SMS-network cannot transmit.
- 📱 Use of more 3-4 complex emojis in one message often trigger conversion.
- 🎨 Use of color text or special fonts from the themes of design MIUI.
- 📎 Automatically add a signature or business card to the message.
- 🌐 Having links that the system recognizes as a preview (although usually links pass as text, sometimes previewing a site requires a preview). MMS).
You should be especially careful about stickers. Even if you send a sticker to a chat that only supports text (for example, when switching from Wi-Fi to a mobile network in saving mode), the system will try to send it as a picture. At this point, a forced transfer channel switch occurs. To avoid this, it is recommended to turn off the auto-conversion function in the settings, if this option is available in your firmware version.
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If you want to send a long text from an emoji and you want to stay within the SMS, break the message into two short ones. This is guaranteed to stay in the SMS protocol, although it will come in two parts.
Settings of the Messages application in MIUI and HyperOS
Xiaomi’s shell interface hides a lot of useful settings that directly affect the behavior of the messenger. By default, the system seeks to provide the best user experience by sending messages in high quality (RCS-To check the current settings, you need to go to the message app, click on three dots or profile icon and select Settings.
The settings section often contains the option “RCS Chat” or “Enhanced Messages.” If this feature is active, the phone tries to send a message over the Internet as in a messenger (WhatsApp or Telegram). If the Internet is unstable or the recipient does not support the function, the message can “stuck” or convert to MMS to guarantee delivery. Disabling this feature returns the classic mode of operation.
Path to setup: Messages → Settings (three dots) → RCS Chat → Turn offAlso, you should look for Message Limit or Input Mode in the settings. Some versions of HyperOS have a Send as MMS option that can be activated randomly. Make sure you check the "Limit MMS" box or similar box to alert you before sending a heavy message, which will help you monitor costs and understand what exactly is happening in the background.
☑️ Checking message settings
Problems with APN and access point settings
Often, the reason lies deeper in the APN settings of your mobile operator, and it is through these settings that the phone understands how to connect to MMS gateways. If the APN settings are incorrect or there is no MMS data, the phone can behave in an unpredictable way: either not sending anything or trying to send everything as an MMS through a standard Internet gateway, which causes errors or unnecessary write-offs.
To check this, go to Settings. → SIM-maps and mobile networks → Choose yours. SIM-map → Access points (APN). The profile of your operator should be selected here (for example, MTS, Beeline, Tele2, Megafon. if you see a profile with a name «MMS», Make sure it's set up correctly. Sometimes it helps to reset. APN factory-level.
| Parameter | Value for MMS (example) | Importance for the Internet |
|---|---|---|
| Name (Name) | Operator MMS | Operator Internet |
| Type APN | mms | default,supl |
| MMSC | http://mmsc.operator.ru | (empty) |
| proxy | 192.168.192.192 (example) | (empty) |
Critical: If the field is "type" APN» For your main profile, you have mms instead of default or the Internet, and your phone will try to send all traffic, including regular messages, through the Internet. MMS-It's a common mistake after manually configuring or resetting the network.
How to reset APN settings on Xiaomi?
The Impact of Google System and Application Updates
Google regularly updates its messaging app, which is often the standard for Android, even if Xiaomi uses its own. Updates can change the logic of the RCS (Rich Communication Services) protocol. After another update, you may notice that messages have started to leave differently, which is because newer versions are more likely to use Internet channels by default.
In addition, updates to the MIUI or HyperOS firmware itself can reset some privacy and network settings, such as app permissions for Android 13 or 14, which could change, and the messaging application could lose access to the background data transfer for SMS and compensate for this by switching to MMS, where other rights are required.
- 🔄 Updating Google Messages app to beta could include experimental chat features.
- 🛡️ Android Security Policy Changes Could Block Background Submissions SMS without explicit user action.
- 📡 Failure of the communication module after the firmware update requires rebooting network settings.
If the problem started immediately after the update, it makes sense to clear the Messages cache. Go to Settings → Apps → All Apps → Find Messages → Clear → Clear the cache. This will not delete your correspondence, but will correct possible software errors in the module.
Third-party applications and software conflicts
Many Xiaomi users install third-party launchers or alternative SMS apps (e.g. Textra, Pulse SMS) to get more features. Such applications often have their own conversion settings that prioritize system ones. If you use third-party software, check its settings first. There may be a checkbox that says "Always send as MMS" or "Use compression" that works through a multimedia protocol.
Antivirus applications or spam blockers can also clash, intercepting an outgoing message, analyzing it, and trying to check for viruses or spam, changing its title or mode of transmission, which in rare cases leads to a clear text message being sent as an MMS.
⚠️ Note: Third-party applications may request excessive permissions if a flashlight application or calculator requests access to the app. SMS and MMS — This is a cause for concern. Check the permission list in Settings. → Protection of confidentiality → Permit Controller.
For diagnostics, try temporarily disabling all third-party apps that work with contacts and messages. If the problem disappears, then the conflict was caused by one of them. On Poco and Redmi smartphones, topics that change the interface of the caller and messages are popular. Changing the topic to the standard often helps to determine whether the visual bug of the topic is the cause of the incorrect display of the status of the message.
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Most often, the reason for turning SMS into MMS lies in the combination of long text, the use of emojis and active settings. RCS-Disabling Internet chats in message settings solves 90% of problems.