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Is KittyUI v4 Safe to Install?

Publisher: Basanta · KittyUI Theme · Last updated: 31 October 2026

KittyUI v4 is a free theme by NVX Boss on the official Xiaomi Theme Store. On my Redmi Note 14 5G Global running HyperOS 3.0, I installed it from that store and used it for about a month. I did not lose files, apps, or settings. That result is from one phone. It is not a promise that your phone will do the same.

The theme changes system screens: the lockscreen, icons, control center, dialer, and status icons. It needs Xiaomi's Themes app. A third-party installer that asks for Accessibility access is a higher risk, and I did not test that tool. This page is the safety answer and the disclaimer for kittyuitheme.com.

What I saw on my phone

I am Basanta. The install I trust is the one I did myself from the Theme Store, through the Themes app, with no root and no computer. After a restart I entered CAT17 under Themes app → Profile → Lock Style → Customize → Password. The themed lockscreen then worked, including the charging animation and the widgets I toggled.

During that month the theme did not delete my files, remove my apps, or wipe my settings. I also saw glitches: overlapping UI until I restarted, a notification area that looked like stock HyperOS until I locked and unlocked, and a depth-effect wallpaper that went flat after a Theme Store update until I toggled Depth of field effect off and on.

Those glitches were annoying. They were not data loss. I still want you to back up anything you care about before you apply a theme, because my month is not your phone.

What safe does not mean here

Safe, on this page, means a narrow thing:

  • The copy came from Xiaomi's Theme Store, not from a random upload
  • On one Global Note 14 5G with HyperOS 3.0, a month of use did not delete my data
  • I did not need root

It does not mean:

  • Every Xiaomi, Redmi, or POCO phone will accept the theme
  • A .mtz file from another website is the same file I installed
  • The look will survive every Theme Store update
  • Xiaomi's warranty terms are something I can decide for you. I did not unlock the bootloader or root the phone. I cannot tell you how Xiaomi treats a Theme Store theme under warranty
  • A battery, heat, or speed measurement. I did not run one

Does KittyUI v4 need root?

The official store method did not need root on my phone. If a page asks you to unlock the bootloader, flash a ROM, or install a module to get this theme, that is a different project from the one I tested.

Is CAT17 a system password?

No. CAT17 is a code the theme asks for inside the Themes app, at Profile → Lock Style → Customize → Password. On my phone it revealed the themed lockscreen, the widgets, and the themed control center. It is not the PIN that unlocks your phone. It is not a Xiaomi account password. It is not an Apple ID. Do not type your real lock PIN into that theme field, and do not send CAT17 or your PIN to me by email.

Entering CAT17 did not hand me extra system permissions. It also did not unlock every visual feature on day one. Depth-effect wallpapers and some widgets arrived later, or after an update.

The Theme Store route and the third-party route

Use the official Theme Store if the Themes app is on your phone. The taps are in the install guide: https://kittyuitheme.com/#install

The MTZ Installer path is for people who cannot open the store listing and only have a .mtz file. I did not test it. It is a third-party app, not a Xiaomi app, and it asks for Accessibility access plus battery exemptions. Accessibility access lets an app read what is on the screen and perform taps. I did not grant that for KittyUI v4. I do not recommend that route as the normal install.

This website does not host the theme file. A download button on some other domain is not my file, and it is not automatically Xiaomi's file.

Phones I would not tell you to try this on

  • Any phone without Xiaomi's Themes app. The official route needs that app
  • Realme, OPPO, vivo, Samsung, Infinix, and other non-Xiaomi phones. I have not tested them, and I would not expect a MIUI or HyperOS theme to apply
  • A phone that already reports the theme as not compatible. I have not reproduced those reports, and I do not have a bypass
  • Anyone who wants the Dynamic Island-style widget on the home screen. On my phone it was on the lockscreen only
  • Anyone who expects CAT17 to switch on every feature the moment it is saved

Back up first

I did not lose data. You should still copy off photos and anything else you cannot replace before you change a system theme. A theme edits how the phone looks. It is still a system-level change, and the removal steps back to the Default theme are not a test I have confirmed on the page yet.

Trademarks and who is not behind this site

I publish KittyUI Theme. NVX Boss designs KittyUI v4. Xiaomi operates the Theme Store, MIUI, HyperOS, Redmi, and POCO. Apple makes iOS. None of those companies run kittyuitheme.com, and none of them asked me to write these pages.

Xiaomi, Redmi, POCO, MIUI, and HyperOS are trademarks of their owners. iOS, iPhone, and Dynamic Island are trademarks of Apple. The theme imitates an iOS-style look. The words on this site are mine. The theme design belongs to its designer.

No warranty

The guides describe what happened on my phone. They can be wrong for yours, and they can go out of date when the Theme Store ships an update I have not installed yet. To the extent the law allows, I am not liable for lost data, a theme that will not apply, time spent fixing a screen, or a choice you made from a sentence here. If a consumer law where you live does not allow that limit, it applies only as far as that law allows.

This page is not legal advice about your phone, your warranty, or a dispute with a seller. It explains the limit of my test and the limit of this site. Questions and corrections go to classytechstudio@gmail.com.

Questions people ask

Is KittyUI v4 a virus?

The copy I installed came from the Xiaomi Theme Store through the Themes app. On my Note 14 5G it did not delete files or install a second app during about a month of use. A .mtz from a random download site is a different file, and I did not test those files.

Will KittyUI v4 delete my photos or apps?

It did not delete mine. Back up first anyway. My result is one Redmi Note 14 5G Global on HyperOS 3.0.

Is CAT17 a hack?

No. It is a password field inside the theme's lock-style settings. On my phone it turned on the themed lockscreen. It did not give me root or extra system permissions.

Do I need root or a PC?

No, not for the official store method I used. I installed and applied KittyUI v4 on the phone.

Is KittyUI Theme the official Xiaomi or NVX Boss site?

No. This is my independent test site. I am Basanta. I am not affiliated with Xiaomi, NVX Boss, or Apple.