Older versions of Yousician - the popular music education app that implements a "rhythm game" like Rock Band or Guitar Hero but using real instruments - included several ways to add custom songs the service.
In previous versions of Yousician, one could:
A. Create a custom, single-track song from scratch using Yousician's own in-app tab editor, as demonstrated in this old walk thru from YouTube.
B. Add a pre-existing transcription by uploading a file in the GuitarPro (*.gp5, *.gp4, *.gp5, *.gpx) format. As briefly seen here, songs added in this way could even contain multiple, independently playable tabs.
C. Import an audio file - by extracting the soundtrack from a YouTube video or directly uploading an MP3 - to programmatically generate a musical score via a process sometimes known as "Automatic Music Transcription" or "AMT".
In the former cases, custom songs would be accompanied by synthesized audio generated from the imported or manually created score. In the latter case, songs would be backed by the imported audio track itself, natch.
These tools weren't perfect - the song editing interface was a little clunky and the automated transcriptions often required a bit of tweaking - but they were extraordinarily powerful. You could apply Yousician's engaging gamified feedback to a song of your choosing with only a modest of amount of manual effort, even if your ability to transcribe a song "by ear" was limited. And custom songs could be shared with other users, so you had access to a "long tail" of custom tabs without even adding songs on your own.
Yousician introduced support for custom songs in 2016 in a blog post entitled "Open Platform", declaring "now users can upload or create their own songs and exercises". These features were immediately popular, with many users - your author included - enthusiastically embracing the opportunity to add their favorite songs to the platform despite the occasionally tedious manual labor needed to ensure an accurate transcription.
Unfortunately these features were relatively short lived. Yousician announced plans to "sunset the song upload feature" in mid-2018 and completely removed all user-generated content from the app with the release of version 2.58 in October of that year. Presumably this change was made in support of their new "Premium Plus" tier, adding transcriptions of popular songs backed by studio recordings by the original artists on top of the existing freemium/paid offering primarily based on "sound-alike" songs credited to Yousician's own in-house cover band collectively known as "The Yousicians".
The decision to remove all custom songs from the Yousician platform - both private and shared - was a controversial one. The original announcements and much of the contemporary reaction seems to have been since scrubbed from the Internet: including the release notes for the v2.55 and v2.58 updates (announcing the pending introduction of Premium+ "popular songs" feature and finally removing all custom content, respectively) and several of the most active user forum responses from the time (some of which are archived on the Wayback machine here, here, and here.) The ability to import custom songs into Yousician continues to be one of the most frequently requested features on Yousician's own feedback forums (as well as other places around the web), but the company has consistently rejected the request. The Yousician team seems to be committed to this strategy.
Installing an Older Version of Yousician
It's a testament to the utility of this feature that even today - more than 3 years after the capability was removed - you still come across fresh posts on Reddit and other guitar forums that ask some version of the question "Can I install an old version of Yousician that supports custom songs?" (example 1, example 2).
The short answer is "no". That's a terrible idea. Not only is this an ethically questionable decision at best - violating the spirit and probably the letter of Yousician's terms of service - it's almost certainly not going to work anyway. The Yousician client isn't a stand-alone app. It depends on a server-side component - at least superficially and likely quite fundamentally - in order to operate. It will be difficult if not impossible to "spoof" the server-side functionality effectively, prone to break even if you got it partially working, and of limited utility anyway absent the "back end" services no doubt required for the custom song import. Even in the best case scenario you're likely to be left with a version of the Yousician app that's capable of supporting custom songs, with no practical source for the custom content itself.
Moreover, any "cracked", older version of the Yousician app you might find on a "warez site" or other repository of pirated software is extremely likely to include malware - computer viruses, ransomware, or other malicious software designed to compromise or exploit your device, your data and your privacy.
The temptation is understandable, but trying to install an older version of Yousician with the hope of being able to play custom songs truly is a terrible idea. It's unlikely to work in the first place (for the reasons mentioned above) and extraordinarily risky to attempt.
Alternatives to Yousician Custom Songs
You love the power of rhythm game mechanics, but aren't content with the scope of anyone's "official" song catalog. No amount of premium or DLC content is going to cut it. You want to play your own songs. So what's a guitarist to do?
Adding songs to Yousician is off the table, unfortunately. The Yousician team dropped support for custom content years ago and show absolutely no interest in revisiting that decision; if anything they seem more committed to that strategy than ever.
Luckily, while there's no "drop in" replacement - no perfect point-by-point match for the capabilities that Yousician abandoned back in 2018 - there are a number of viable options that approximate the core functionality, including our very own FATpick. Some alternatives to adding custom songs to Yousician include:
Ultimate Guitar - Ultimate Guitar is a tab player for the web and mobile devices. In addition to an extensive catalog of songs shared by other users (and/or scraped from historical collections of guitar transcriptions), you can add new songs by importing Guitar Pro files (and similar tab-sharing formats). Ultimate Guitar does not however include an audio analysis component. It's a tab viewer with synthesized backing audio tracks, but not a full rhythm game in the style of Yousician, Rocksmith, or FATpick. UG is a tab player designed to be played along with, and supports custom songs, but without the note/pitch detection features required to support gamified performance feedback.
Rocksmith - Rocksmith+ (like its predecessor Rocksmith 2014) is a robust arcade-style rhythm game for desktop computers (Windows or Mac) and gaming consoles (Xbox or Playstation) featuring licensed transcriptions of popular songs backed by audio recordings from the original artists. The official catalog is limited - individual songs or bundles that can be purchased, downloaded and added to the game as DLC. But Rocksmith users have developed means of creating and distributing unofficial song content that can be "side-loaded" into and played within Rocksmith. It is labor intensive to create Rocksmith song files, and requires some technical sophistication to import them, but tools like Customsforge and Rocksmith Toolkit make it possible to add arbitrary songs to your Rocksmith catalog. These tools exist in a somewhat gray area relative to Ubisoft's terms of service for the Rocksmith platform, but as a practical matter the custom content community is on excellent terms with the company. Ubisoft doesn't outright endorse these custom song creators, but has a well-established policy of at least looking the other way. Thanks to a small but thriving community of volunteer content creators a large catalog of high fidelity songs are unofficially available to be added to Rocksmith.
FATpick - FATpick is rhythm game that supports custom songs, and arguably comes closest of the three options to replicating the missing functionality. Like Ultimate Guitar, FATpick includes a library of previously shared songs, and allows users to add their own songs by importing tabs from arbitrary Guitar Pro files. Like Yousician, FATpick renders the imported songs in a side-scrolling tablature view, synchronized with backing audio tracks, and uses audio analysis to provide gamified feedback on your pitch and rhythm as you play along.