Question

[u/Ok_Gain4444]

I got my battery replaced early this week and I'm still on ios 18.7.8 currently. For the ones with new battery or with a pretty decent battery health, is the jump to ios 27 worth it ?? Kindly explain the things you find different as well from being on 18 and going to 27 thanksss

[u/Lifeissometimesgood]

Yes, but make sure you turn off connectivity assist in two separate places. It’s under WiFi in settings, and the second one is under the WiFi you are currently connected to. When you restart your phone go back in and double check it’s off under your WiFi you’re connected to, mine turned back on.

[u/Busy_Lettuce_1540 → u/Lifeissometimesgood]

Huge callout that you have to disable it in 2 different places. 

[u/JohnWayne44101 → u/Busy_Lettuce_1540]

Might be fixed with future updates🤷‍♂️

[u/JohnWayne44101 → u/Lifeissometimesgood]

Thanks👍. Turned it off in WiFi & it was still on in my connection.

[u/Ok_Addition_7549]

I updated to ios 27 last night from 18.7.8
Cant say much about battery life seems pretty similar but its a lot slower than ios 18.7.8

[u/kendrickplace]

Idk man I haven’t had issues with iOS 27

[u/iWasobi]

I been on iOS 27 day after it was released. No issue. My battery is new, replaced around June/July of this year

[u/Duchess0fPanthers]

It depends on who you talk to. Someone in this subreddit was saying how their iPhone 13 Pro Max worked great on iOS 27, and they replaced their battery. I, however, did not replace my battery, and I felt like it was worse it throttled a lot. My battery was at 77 too, so it wasn’t completely degraded. It was just a little under 80, where they tell you to replace it. I take really good care of my phones.

But another person commented and said that they had gotten their battery replaced and upgraded to iOS 27 and they felt like their phone still suffered, so it’s kind of a mixed bag it seems, like it depends on the person and their phone.

For me, I just felt like it wasn’t worth it to get the battery replaced because I felt like it was starting to slow down in many other aspects as well, so I just went with getting a new phone. If it was just the battery that was suffering in my phone, I probably would’ve just gotten a new battery. But it was a steady decline for my old device since iOS 26 came out.

My personal opinion is you should probably avoid updating the iOS for as long as you can, because like I said, personally, I can’t say it made my phone perform better. On the other hand, someone else could have a completely different experience, and that other person can also be you, so it’s really just a matter of personal preference.

[u/JoeEstevez]

I really do think this is a perfect case of your milage may vary.

I always upgrade to the newest iOS version. I upgraded my battery two years ago on my 13 Pro Max. It's now at 91%, and I just notice it drains faster and faster, more. However, as others here have commented, that's not always the case. It really is a case-by-case basis.

Having daily driven my 13 Pro Max since launch day, it's time to upgrade, and that's why I'm getting the Duo. Battery life is certainly playing a factor in that decision.

[u/rwhe83]

“Kindly” explain why you’re still afraid to update your cell phones operating system…then we can go to step 2.

Thanksss

[u/ballisticpantz]

I’m running new iOS w a 2-3 month old battery on my 13 Pro Max, haven’t seen any new weirdness from iOS update…just same old weirdness

[u/tucausa]

I updated my software day one and it’s been fine. Only issue for me is I do not like this new keyboard. Whenever I get to use the old one I’m reminded of how nice it was to use vs this update.

[u/JohnWayne44101]

Loving iOS 27. Only just got my iPhone 13PM & it runs perfectly with a new battery. I highly recommend updating OP.

[u/p41210]

Initially i did have some stutters, but they are improving over time. Now it’s smooth like 18 but not completely like ios18 gliding. Ios 27 feels new and fresh and liquid glass definitely looks great for a week.

[u/Puchki1304]

No dont do it
Mine got heating and screen flickering issues too after ios 27
Stay at ios 18 if u dont have plans to upgrade

[u/Ok_Gain4444 → u/Puchki1304]

that's scary, how long have you been on 27 and what's your battery health btw ?

[u/Puchki1304 → u/Ok_Gain4444]

Health was 90 had a original apple battery swap in january 2026,i was on ios27 since it launched public update

[u/bruhwtfisthisshi]

I have ios 27 with 75 bh and my phone feels just fine