Loss of Cell Connectivity After IOS 16.3 Update- iPhone 13 Pro Max

GPTitan Said:

"Is anyone experiencing frequent loss of cell connectivity after updating to IOS 16.3?"

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No. I am not having this issue.

Troubleshooting Cellular Connectivity:

A. "No Service":

Is "No Service" shown on the top-left corner of your screen? If so, go here to fix that: If you See No Service or Searching on your iPhone or iPad - Apple Support

B. No SIM":

"No SIM"*** is shown on the top-left corner of your screen. So, go here to fix that: If you See 'invalid SIM' or 'no SIM' on your iPhone or iPad - Apple Support

C. Contact your Carrier:

Having issues with Cellular, contact your Carrier, asking them to configure this to the correct settings. They configure all of this in the SIM card.

GPTitan Said:

"Is anyone experiencing frequent loss of cell connectivity after updating to IOS 16.3?"

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Report this to Apple:

Do your Part: Provide Apple with feedback on this, letting them know about this issue.  Apple may not get back to you directly, but the more feedback they receive on this, the more they will know what is occurring, and what bug fixes to include in updates to come. Apple probable has received little to no word of this issue.

1. Go Here: Feedback - iPhone - Apple
2. Select: "Bug Report" for the "Feedback Type"
3. Comment: that this all began after installing an update, and how you have troubles it thus far. Include the URL of this post.
4. Proceed from there as necessary

Greyed-out signal bars do not represent your signal level, they represent your possible signal level with the actual signal level denoted by solid black or white bars, depending upon your screen settings.

For example, this represents three out of four bars of cellular signal, a full scale Wi-Fi signal, and a 99% battery charge (I have the Battery Percentage option enabled):

Loss of Cell Connectivity After IOS 16.3 … - Apple Community

Yes!

Tried resetting network settings: worked for a few hours then problem returned

Tried resetting phone with erase all contents and settings, but problem returned

Called apple and they said to try full restore, plugged into Itunes. Waiting to see if it holds. 

Seems Verizon needed to release a carrier update but didn't, and the new IOS can't negotiate with their network very well. apple blames verizon, verizon blames apple. BTW I pulled the sim and put it into another phone with IOS 16.2, and it worked perfectly, so its NOT the sim, or the verizon account that is the issue. It is a fight between the new IOS 16.3 and the cell phone networks.

Tell her to contact her cellular carrier, they are the ones who can resolve the issue.

"SOS Only" mode means no usable signal on the network she subscribes to but there are other cellular signals the phone can connect to (say no AT&T signal but the phone sees a Verizon signal.)

This is the same frequency/base station issue covered in other threads here, and has to do with settings at the cellular tower.

You may also want to do a manual check for a carrier settings upgrade just to be safe:

Manually update your carrier settings on your iPhone or iPad - Apple Support

Why do you believe that?

For example, both the iPhone 14 Pro and Pro Max support GSM/EDGE (850, 900, 1800, and 1900 MHz).

However, the 900 MHz band is not used in the United States, only the 850 MHz and 1900 MHz bands are.

Your watch doesn't use the exact same cellular frequency bands as your phone.

You don't specify which phone, but:

Apple Watch Ultra:

LTE

• 1 (2100 MHz)
• 2 (1900 MHz)
• 3 (1800 MHz)
• 4 (AWS)
• 5 (850 MHz)
• 6 (850MHz)
• 7 (2600 MHz)
• 12 (700 MHz)
• 13 (700c MHz)
• 14 (700 PS)
• 17 (700b MHz)
• 18 (800 MHz)
• 19 (800 MHz)
• 25 (1900 MHz)
• 26 (800 MHz)
• 39 (TD 1900)
• 40 (TD 2300)
• 41 (TD 2500)
• 66 (AWS-3)

UMTS

• 2100 MHz
• 1900 MHz
• 1700/2100 MHz
• 850 MHz

iPhone 14 Pro Max:

• 5G NR (Bands n1, n2, n3, n5, n7, n8, n12, n14, n20, n25, n26, n28, n29, n30, n38, n40, n41, n48, n53, n66, n70, n71, n77, n78 n79)
• 5G NR mmWave (Bands n258, n260, n261)
• FDD-LTE (Bands 1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 17, 18, 19, 20, 25, 26, 28, 29, 30, 32, 66, 71)
• TD-LTE (Bands 34, 38, 39, 40, 41, 42, 46, 48, 53)
• UMTS/HSPA+/DC-HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
• GSM/EDGE (850, 900, 1800, 1900 MHz)

So for example if your carrier's cellular tower antennas are not optimized for FDD-LTE band 8, if the tower's base station controller assigns your Apple Watch to LTE band 7 but your iPhone to FDD-LTE band 8, your watch may work perfectly but your phone may report "No Signal."

You should contact your cellular carrier.

Your iPhone SE 2020 does not support the same frequencies as your iPhone 13, especially if the SE 2020 is only connecting at 4G speeds.

The phones support the following frequencies, I've emboldened those unique to the iPhone 13:

iPhone SE 2020:

• 5G NR (Bands n1, n2, n3, n5, n7, n8, n12, n20, n25, n28, n29, n30, n38, n40, n41, n48, n66, n71, n77, n78, n79)
• FDD‑LTE (Bands 1, 2, 3, 4, 5, 7, 8, 12, 13, 14, 17, 18, 19, 20, 25, 26, 28, 29, 30, 32, 66, 71)
• TD‑LTE (Bands 34, 38, 39, 40, 41, 42, 46, 48)
• UMTS/HSPA+/DC‑HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
• GSM/EDGE (850, 900, 1800, 1900 MHz)

iPhone 13:

• 5G NR (Bands n1, n2, n3, n5, n7, n8, n12, n20, n25, n28, n29, n30, n38, n40, n41, n48, n66, n71, n77, n78, n79)
• 5G NR mmWave (Bands n258, n260, n261)
• FDD‑LTE (Bands 1, 2, 3, 4, 5, 7, 8, 11, 12, 13, 14, 17, 18, 19, 20, 21, 25, 26, 28, 29, 30, 32, 66, 71)
• TD‑LTE (Bands 34, 38, 39, 40, 41, 42, 46, 48)
• CDMA EV‑DO Rev. A (800, 1900 MHz)
• UMTS/HSPA+/DC-HSDPA (850, 900, 1700/2100, 1900, 2100 MHz)
• GSM/EDGE (850, 900, 1800, 1900 MHz)

This means if the cell tower tells your iPhone 13 to use one of the frequencies in bold, it could have difficulties that you will never see when using the iPhone SE because it can't access those frequencies.

At the very least your carrier can help you through additional debugging as they can see whether their network can see your phone or not from their side.

My iPhone 11 Pro will show LTE when in fact it is connected to our WiFi. When the phone “wakes up” is when I notice the LTE designation. Then when I go to an app, it indicates WiFi connection. I have performed all the suggested steps but it’s not our WiFi. All of our other devices are not having WiFi issues. Can’t seem to get this resolved. Wish I could go back to previous iOS version

I’m using the 14 pro max and had the same issue. iMessage/calls worked when talking with others who had an iphone but couldn’t send regular texts or calls on android or landlines. Data up top said I had 5g full bars although they were grayed out. Speedtest on goolge confirmed data was working properly. Anyways my carrier had me reset my network settings and that seems to have fixed the issues so far. Calls/texts to any phone now seems to be working. Starting to think I should have waited to update 😅😅

I have some more details about the problem.

Usually I work from home, the number of times I get disconnected during usual day is nothing compared with when I go out and do some small commute to the office.

When I restart the mobile (iphone 13) I get signal for some minutes (it depends, some times less than a minute and some times more) but suddenly then the signal turns off.

Inside settints - mobile data - network selection I have it on automatic, if I switch off this selection the mobile is unable to find anything. This does not happen with an iphone 11 pro.

Update: It didn't hold.

Took it to Verizon store, and they said the problem is rampant. They had to replace the phone! The phone which was working perfectly in 16.2 is useless in 16.3. OBVIOUSLY its an OS bug with Verizon's servers. May be other carriers too, I don't know. But the store is replacing phones right and left because they can't fix it.

Not necessarily cellular connection issues as far as phone service goes, but since going to 16.3, when I leave the house in the morning and get away from WiFi, I have no cellular data. I’ve been having to reboot my phone every morning in order to correct it

Edit: IPhone X

I reset my Network Settings and it did not solve the problem. Every since I updated to 16.3 after getting the celluar service provider to get my data working it lasts for about 1/2 of a day and then it goes away. This didn't happen until version 16.3 was loaded to my Iphone 10x