Unofficial .apk or .rar files from the internet can contain malicious software. Always verify the source and use antivirus software before extraction.
Patches that modify entire game files can sometimes "ruin" the visual experience or lead to crashes if not properly installed. Unofficial
Using modified patches violates Konami's terms and conditions. While some users report being able to use them without immediate issues, others have experienced temporary or permanent bans for altering game data. watch this demonstration:
For a visual guide on the typical steps required to install modified patches on mobile devices, watch this demonstration: Unofficial