forum.xda-developers.com/android/apps-games/app-viper4android-fx-2-6-0-0-t3774651

Many users are enhancing their smartphone audio experience with the popular ViPER4Android software, but some of us have a hard time installing the driver or they don't like the look of the app. As a solution for these troubles we have rewritten the 2.4.0.1 app source and added all 2.5.0.5 features to it. Many more features have been implemented too.
With our huge success of ViPER4Android 2.6 we decided to completely rewrite the ViPER4Android app in Kotlin. This allowed us to squeeze out the remaining bugs and clean up the code even more. After a long time of waiting for you and developing for us, ViPER4Android 2.7 is finally here!
There are many new features and improvements compared to 2.6, of which some can be found in the changelog. Hit the download button to check it out yourself!


Answers to some related questions

Why does your Magisk module not work?
Probably because you installed some other mod that also has an audio_effects file in it. Whatever module gets loaded last will become active
The easiest way to bypass this is to let the app build a module after you installed all your favorite audio mods, and delete all files containing audio_effects in the other modules
AudModLib will not come in handy this time, because the app doesn't flash a zip that AML can intercept

Where can I find the source code?
You can't. And there is an obvious reason for that: This app is more sensitive to kangers who start selling this app, likely after adding their bullsh*t to it, rather than to people who actually want to help improve the app. Something like that already happened in the past to other audio software here on xda. Not really something we want to see happen again

How come this app only processes music played through the internal music player?
Congratulations, the driver installed successfully. However, that's the way android works after introducing fixes to the overall high latency android had in the past.
Fixing that is not something our app should do in our vision, because this modifies the system more and goes beyond the V4A project.
Zackptg5 has put a lot of effort in time in creating the Audio Compatibility Patch, which tries to deal with it. Highly recommended to check that out in the Magisk repo

Where did the Selinux switch go?
What..? Are you really that careless security wise?
The app handles this in a much more sophisticated way now. It injects only the absolute necessary rules to allow V4A to process, fully automatically

Help, why do I still experience service drops?
Probably because doze is kicking in because Android doesn't like long running services. The service has been implemented the way the docs suggest, so the only thing you can do is exclude it from doze

Why did you revert some layout changes I saw in 2.5?
We didn't. This app is built starting from that old 2.4 holo designed one, because that was the latest open sourced version. We made some good progress already, don't you think?

Do you have a zip file for me?
No. There is no point in providing a zip file anymore. The driver installation is written from scratch and actually works now

Why does the driver uninstall not work?
Because you didn't install the driver using the app. We don't have some magic file cleaner built in that removes all previous installations ever

Why does this one sound better/worse than previous versions?
That's your placebo being strong. It's the same driver, which means the effects are the same too
From version ViPER4Android FX 2.7.0.0:
Major changes compared to 2.6:
- Full rewrite
- New UI
- Presets can be managed in the app itself
- Effects can be set more precisely with seekbars
- Min API 23
- Uses 2.5.0.4 driver only
- Audio routing bug fixed
- Driver status bug fixed
- Cross device effect changing bug fixed
- App follows system dark/light mode (can be toggled with google messages e.g.)
- Installation is faster and more versatile
- Notification settings
- Reduced APK size significantly
All versions
February 6, 2019