Question Are we safe to use 2017 LTS for 2023?

I have tried to upgrade the whole 2017 project into 2021 LTS, after a lot of fix but it still requires a lot of work to make it working, plus the "FPS" performance is dropping a bit.

After a long struggling with 2021 and even tried URP pipeline, It cost us a lot of time just dealing with issue that never had before. and continue to develop it with 2017 LTS seems be the best solution for now, but I'm not sure if the 2017 LTS will be able to port games to AppStore and Google Play and support the latest iOS and Android system.

Our development is in a tight schedule and plan to release this project next year.

 

You should use version control so you can revert easily.
If you're on tight schedule, then upgrading is definitely not safe.

 

We don't need any new features actually, but just worried about the 2017 LTS being too old and not compatiple with latest phone OS, luckly 2017.4 LTS already support arm64

 

Take smaller steps. Upgrading to a +4 version is optimistic at best. Try 2018, then 2019, then 2020. That way you can focus on fixing the issues caused by each upgrade rather than all of them at once. It may seem like 4 times the work but in fact it can actually make the upgrade process smoother, and you‘d have the option of staying on say 2020 if the 2021 upgrade causes particularly difficult/time consuming upgrade work.

I wonder why you are on 2017 though while being on a tight schedule as well. Something tells me you haven‘t been working on this for five or more years. Reminds me of the devs these days: „2019.3 is the best“ and so on. And then, when they want to publish in 2023 they‘ll slam their head in getting old tech to work with new tech, if at all possible.

Whether 2017 is still compatible with modern mobiles is something you can easily find out whether it‘s not: make a build.
If even that fails you don‘t even have to consider submitting to stores. And if it works, you can submit it for approval. While/after uploading an automated check runs to test for compatibility issues.

Personally I seriously doubt it. With a release next year you‘re looking at releasing a game built on six years old tech, with mobiles getting major OS releases every year and in general support for devices older than four years being dropped. So you‘re working with tech that was built to support and run on devices and OS versions that today are all deprecated and do not receive new major updates anymore. It sort of feels more like common sense than having to check feature lists to determine that this is almost certainly not going to work.

 

You got a point, and that's why we're seriously considering using 2021 LTS.

Actually I have made almost everything working in 2021 LTS now, just missing some performance(about 7ms and about 10 fps difference just in rendering with exactly the same scene, the script is running a little bit faster in 2021 as we optimized something) .

After examing the Frame Debugger. we got about 20-30% more drawcalls than the old one in 2017, still looking a way to make the 2021 version to have the same performance as the 2017 one.

 

Mobile requirements are announced months in advance and existing apps receive longer to meet them than an app that is ready for release. For example iOS's 64-bit requirement only gave 6 months to new apps but ones that were already released had 12 months to be updated.

https://developer.apple.com/news/?id=06282017a

 

Note
Unity xxxx_1 = Pre-release
Unity xxxx_2 = Tech-release
Unity xxxx_3 = Official-release LTS

Official - 2021.2: iOS Minimum Supported OS - Unity Forum

Android Minimum API Level Change - Unity Forum

when upgrading from a version that old you will certainly find some problems that will need to work thru
some small lessons that may help save you some pain
-- do not use nested prefabs as they will break in porting to higher unity versions
-- if you have terrain pre 2019 it cannot be ported .. you will need to find a way to do it with the splat into a new terrain
-- if you use TextMesh do not save them into prefabs, just keep them as-is or porting will break

cheers

 

Unity's yearly versioning has only had TECH and LTS.

https://blog.unity.com/technology/switching-to-two-releases-in-the-2020-tech-stream

 

your correct
the term pre-release i believe now covers the Alpha an Beta versions per Unity HUD

Unity xxxx_1 = Bad Egg
Unity xxxx_2 = Tech-release
Unity xxxx_3 = Official-release LTS

 

Thank you guys, After some deep research I realized the profiler in 2017 defines the redender thread time differenly than 2021, but actually the performance is more or less the same D)

We didn't run into other problems now with 2021 LTS, It took me about 15 days to gradually upgrade it from 2017 to 2021 and solved most of the errors and editor crashes.

 

2021 is definitely far from "safe" but its likely mostly usable
CTRL-Z might crash your editor so always save before CTRL-Z in the scene
We think the rule of thumb is to wait until end of the year with LTS if you don't want constant disaster

 

Use 2020Lts instead as it has been out for long enough to be actually stable. We tried 2021Lts on mobile and ran into multiple stability issues