[Xperia Z3 Q&A, Help & Troubleshooting] RockStar2005:
I think I tried that and it wasn't enough for me, but test it anyway.

In addition to what I said, I did a factory reset using Sony's PC Companion software, and now my phone is FINALLY working flawlessly. Not saying all Z3 phones having these issues have to do this, but I did and it worked. The following is a result of HOURS of research and trial & error:

All,

I use Textra since the Z3's stock messenger app clearly CANNOT handle MMS properly. This is what worked for me....................

Before setting up your Z3 to be able to handle MMS messages correctly, as well as enabling Smart Call Handling to ACTUALLY work, you must do the following which will do both a factory reset AND re-update your phone. My software must’ve been corrupted at some point because after doing this, my phone worked much better. The battery life had gotten really bad but now it’s back to incredible again. My phone works 100% for the first time ever (just no VoLTE ((for now at least)), but who cares, I don't get it in my area yet anyway!!

** Sony PC Companion Instructions:

We have an extended guide that should help you fix the issue on your phone, please follow the instructions carefully:

Visit this link:

http://www.sonymobile.com/us/tools/pc-companion/

Click on Download PC Companion

Run the software and install it

Turn the phone off and disconnect it from the computer

1. No matter what the program says do not connect the phone until you complete step 9

2. In the welcome screen you will see the different modules available for you including the "Support Zone" option. Click on "Start" below it.

3. On the next page Click on "Start" under "Phone Software Update"

At this point if you get an error stating that "Unable to install update components" or "Server is busy" , then please proceed to step 12

4. The program will say that there is no phone connected. Click on the option below that reads: "Repair my phone" the program will issue you a warning about the content that you will lose during the update

5. Choose the option to continue.

6. The program will issue a final message warning you of possible data lost during the update. Click on the checkmark and then on "Next".

7. After that, the program will download the necessary information (5 to 6 minutes) and it will present you with a list of phones.

8. Choose your phones model from the list then click on "Next" then you will see a new section telling you how to connect the phone. (don't connect it yet) (YOU CAN FIND YOUR PHONE’S MODEL # BY DOING THIS: SETTINGS-->ABOUT PHONE-->MODEL NUMBER)

At this point the phone must be off and disconnected from the PC.

9. Connect the cable to the PC not to the phone, then while pressing and holding the indicated button (in the steps on screen an specific button will be shown for you to press on the phone) connect the cable to the phone and keep holding the indicated button until the program says "the update of your phone has started..." (in some cases a message of "Installing drivers" will appear before the message of "the update of your phone has started..." is shown.)

10. If you failed to follow the steps correctly the phone will turn on and it will request that you "Proceed with the following steps, slide down the notification bar", If this happens disconnect the phone from the cable, turn it off and repeat from step 9).

11. If the phone is connected properly, PC Companion will proceed with the update ( It will tell you to let go of the back key) then wait for the update to finish and follow instructions on screen to disconnect the unit.

Dear Customer,

12. If "Unable to install update components"

1. Close PC Companion

2. Install Java from: http://www.java.com

3. Start PC Companion again and try to do the software unlock process once more.

Note: If you wish only to update the unit wait for the program to open and then select the quick link on the upper left corner that says "Update Phone/Tablet" and follow the instructions to perform the update. (the PC may request for the phone to be placed in Mass Storage mode. Do this by going into Settings>Xperia>Connectivity>USB connection mode)

Now that you have completed the PC Companion part, follow these instructions carefully to restore MMS and Smart Call Handling:

1) Add a NEW APN (Settings-->More-->Mobile networks-->Access Point Names ((APN))-->push the + sign button) using these settings (and make sure to select it after creating and saving it):

Name: T-Mobile Data 2

APN: fast.t-mobile.com

Proxy: not set

Port: not set

Username: not set

Password: not set

Server: not set

MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc

MMS proxy: not set

MMS port: not set

MMS protocol: WAP 2.0 <---(DOES NOT APPLY TO THE Z3, BUT OTHER PHONE USERS MAY WANNA TRY IT)

MCC: 310

MNC: 260

Auth Type: not set

APN type: default,mms,supl,admin,hipri

APN proto: IPv4/IPv6

APN roaming proto: IPv4/IPv6

APN enable/disable: enable

Bearer: unspecified

2) ENABLE Stock Messenger app, making sure in "App info" screen (in Settings) that the "Notifications" box is unchecked. (Not sure if unchecking it matters, but I'd do it anyway to avoid double notification of incoming texts.) Also, under Stock Messenger's settings, make sure ALL boxes are unchecked as well.

3) In Textra (download this great text SMS/MMS messaging app if you haven't already from Google Play Store), make sure it's your default app, under Settings, "Use MMS for Group Chats" should be checked, MMS Settings: No Limit, and check the T-Mobile Wifi Calling Fix box too.

4) In Phone settings, under Call Settings, uncheck/disable: VoLTE. (VERY IMPORTANT!) (Note: Maybe after Lollipop is deployed you can try enabling it and see if MMS and Smart Call Handling work again, but there’s no guarantee of that.)

5) You can leave STAMINA mode on (under Settings-->Power management), however...... only enable the "Extended Standby" option and of course Activation should be at 100%/Always on. Also make sure “Queue background data” is enabled too. You must also have whitelisted 2 specific apps in STAMINA under the "Apps active in standby" list: The text msg app you're using (i.e. Textra, etc…. the stock app will NOT be listed though) and I would also whitelist one under "All others" entitled "Phone/Messaging Storage". Keep the other stuff disabled in here. With regards to STAMINA mode:

5.1) OPTIONAL: IF AT ANY POINT STAMINA MODE IS NOT WORKING (i.e., WITH IT ON AT 100% POWER, IT SAYS ON STAMINA MODE SETTINGS PAGE THAT YOU HAVE ANYTHING LESS THAN 5 DAYS AND 3-4 HOURS FOR ESTIMATED BATTERY TIME), THEN FOLLOW THESE INSTRUCTIONS: Turn off STAMINA mode. Go into Settings, Apps, All, Extended Standby Mode Controller, Clear Data AND Cache. Then go to your text app's (Textra, stock, etc….do it for all texting apps you have) "App info" page (on same Apps "All" screen) and clear ONLY the cache, then close out the app itself (3D button to the right of the virtual Home button, swipe the text app(s) off the screen). Reset. When you come back, follow what I said above, including turning STAMINA mode back on. Then do as instructed in “5)” above.

6) Put “Keep Wi-Fi on during sleep” to "Only when plugged in" (Settings--> Wi-Fi--> Advanced). Also, make sure everything else on that page is unchecked/disabled.

7) OPTIONAL: IF HAVING ISSUES RECEIVING TEXTS FROM IPHONE USERS WHO HAVE iMessage ENABLED ON THEIR IPHONE, THEN FOLLOW THIS: And lastly, there’s the “iMessage” issue ppl like myself are/were having (also those with LG G2 I’ve heard have this issue too) where when someone with an iPhone sends you an MMS pic text msg while their iMessage option is on, you don’t get the text…….. try this (a T-Mobile store rep told me this and it worked!): send YOURSELF an MMS photo text msg but include at least one other phone # as well too. If you’re using Textra or anything besides just the stock text app, then do this for EACH app. If that is the case, then do it via stock app first then Textra (easier this way). If you receive the pic successfully, then ask anyone you know with an iPhone to send you an MMS message (preferably having a 3rd phone # in on it too, but not sure if you need to) with iMessage ON. If you receive it, then it worked. If not, try this again.

What I just said here MAY resolve any lingering MMS issues, and also resolve any issues regarding STAMINA mode not kicking in too.

It seems that MMS messages will def show up if Wi-Fi is on, but it will take longer to show up if screen is off. Maybe 3-5 minutes longer.

If you have any questions, let me know.

P.S. This ALSO fixed my Smart Call Handling issue where it wasn't working, but now is.

RockStar2005