I can't update my iPhone SE

Your device is probably not connected to the internet. There are a few steps you can take to verify the connectivity of your device.

Firstly, you can open a web browser on your device. When you open a web browser, the initial page that loads is typically based on your browsing history or cookies. To further confirm the connection, you can tap on any link on that website. If the link opens and displays the corresponding content, it confirms that your device is indeed connected to the internet.

Another method to check internet connectivity is by opening a specific application that requires an internet connection. WhatsApp is an example of such an application. When you launch WhatsApp, it immediately attempts to establish a connection with its servers to synchronize your chats and display any new messages. If you can see your chat conversations and receive real-time updates, it indicates that your device is connected to the internet.

Connecting to Wi-Fi is the initial step, followed by establishing an internet connection.

However, it's important to note that connecting to Wi-Fi does not automatically guarantee an internet connection. In the event that you are unable to connect to Wi-Fi, the issue may stem from settings on your iPhone or the router/modem.

On the other hand, if you are unable to establish an internet connection despite being connected to Wi-Fi, the problem is likely related to the settings on your router/modem. In such cases, it is advisable to promptly contact your Internet Service Provider (ISP) for assistance.

Check your WiFi Router / Modem for --> Recommended settings for Wi-Fi routers and access points ...

Connecting to Wifi is the first part and then getting connected to the Internet is the second

1. If you connect to Wifi, doesn't necessarily mean you are connected to the internet. If you are not connected to wifi could be a problem with iPhone settings or Router/Modem Settings
2. If you are not connected to the internet is the sole issue of Router / Modem Settings. Contact your ISP immediately

For your Internet connection.

• Over Cellular: contact your Carrier (Cellular Service Provider). The agency who issued the SIM to you
• Over WiFI: Contact your ISP (Internet Service Provider), the agency who provided the Internet Service on your Modem/Router to you

However --> Connect iPhone to the Internet - Apple Support

There are only 2 ways to update an iOS/iPadOS. Know how to...

• Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
• Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

Before any iOS / iPadOS update, please do the following

• You need to Identify your iPhone model - Apple Support
• It is also recommended that you either take a backup on iTunes or iCloud --> How to back up your iPhone, iPad, and iPod touch
• If you have a beta profile installed, remove the public beta by deleting the beta profile

Go to Settings > General, and tap Profiles & Device Management. Tap the iOS Beta Software Profile. Tap Remove Profile, then restart your device --> How to uninstall iOS beta software - Apple Support

VPN or proxy connections might prevent your device from contacting the update servers.

• Get help with over-the-air iOS updates - Apple Support
• Remove and download the iOS update again

If you still can't install the latest version of iOS, try downloading the update again:

1. Go to Settings > General > [Device name] Storage.
2. Find the iOS update in the list of apps.
3. Tap the iOS update, then tap Delete Update.
4. Go to Settings > General > Software Update and download the latest iOS update.

If you don’t see the update in the list of apps or if the issue happens again, you need to update your device with iTunes.

Try updating iOS after each step.

• Try to Forget the WiFi network and add it again
• Try another WiFi network 
• Toggle sets automatically off and then on
• Reset your network settings
• Force restart your device
• Remove any beta profiles, if applicable

• If everything fails: - Use iTunes or Finder (for macOS Catalina+) to update your device instead of over-the-air
• Get help with iOS updates and restore errors - Apple Support
• If you see an error when you update or restore your iPhone, iPad

Bearing in mind that an iPhone SE 1st generation can support iOS 15.7.7, no further, and that SE 2nd or 3rd generation support iOS 16 or later, assuming you're trying to update your device wirelessly, and bearing in mind that to perform such a procedure you need to connect your device to a reliable and fast Wifi Network with Internet access (no cellular data, unless you use a 5G network, no personal hotspot on your device, no VPN connections are admitted, no Low Power Mode enabled, and I suggest that you keep the device plugged into power during the whole update process), read this support article:--> If your iPhone, iPad or iPod touch won’t update (if you don't have a reliable and fast wifi network, "borrow" one from your relatives/friends/neighbors).

Also, make sure your device is NOT running a Beta operating system version. Should be this case, you need to remove it before installing any official iOS/iPadOS releases, as per these instructions:--> How to uninstall iOS or iPadOS beta software - Apple Support.

DO NOT forget to create a full backup of your device before updating its operating system, and keep in mind that, depending on the available storage on your device and/or on your wifi network speed, it might take 30-60 minutes to complete the entire update process.

If the issue persists or if the iOS version currently running on your device is very old (from your product list, it seems that the device is still running the prehistoric iOS 13), try to update it via computer (if you don't have a computer borrow one from your friends/neighbors, or ask for help at an Apple Store or Authorized Service Provider), then learn how to update your device manually if you're using a Mac with macOS Catalina or later, or if you're using a Mac with macOS Mojave or earlier or a Windows PC.

If you still get no help, contact Apple Support directly, using this link:--> Get Support

Regards

Giulio