The API 3124+ is listed on the Syro album packaging as being one of the many pieces of gear used on the recording of the album.

"For the benefit of any other musicians out there I thought I'd outline the basics of the new system. For the audio portion we're running two Macbook Pros, each with a set of RME UCX interfaces running in tandem via ADAT connected to them (we were previously using 2 single RME Fireface 800's). The ADAT tandem mode allows for more inputs and outputs per computer in one rackspace. The first machine handles playback of automation, SMPTE timecode for video sync, MIDI sync, and our in ear monitoring system (Sennheiser G3 IEM). The second machine is linked to the first via MIDI sync and handles all input channels, virtual instrument hosting and effects processing. Both machines are running Reaper with each project in its own tab. We were running into a lot of resource limitations when the entire set was on one computer so the only way to open things up and allow us to expand the set was to distribute the load across multiple machines. I also just switched to an API 3124+ for the front end of the input laptop as it fits 4 preamps into one rackspace, and it sounds amazing. We run the bass, guitars, and synths through it which lessens the amount of plugins we have to use to get a good tone inside the box."

Used on guitar for the Take Me to Church EP, as stated by mix engineer Rob Kirwan in this March 2015 Sound on Sound interview.

“Guitars I generally record using an SM57 and a Sontronics Delta. The former will go through a ‘lunchbox’ Neve 1073 copy, and the latter through an API 3124+. I’ll compress that with the ADL 100 and an LA2A. The Delta is a ribbon mic, and I use it a lot. I like Sontronics’ ribbon microphones. They give you that ribbon sound, but the problem with a lot of traditional ribbon mics is that the gain is so low that you end up bringing up a lot of noise to get them to speak. I don’t think it is worth it, whereas the Sontronics microphones require phantom power to start off with, which is pretty wild, and they are loud. They really complement the 57. The Delta mic gives the guitar lovely warmth and big bottom end, and the 57 picks up the edgy stuff in the middle. I use those two microphones on pretty much every guitar amplifier that I record."

the API 3124 can be seen in the image

Toru Kitajima uses the API 3124+ in his Studio SAUNA, as confirmed in an interview with サンレコ 〜音楽制作と音響のすべてを届けるメディア, authored by matumo-i_rittor.

You can see the Mic Pre behind Logic connected to his studio desk from 7:23 to 7:45

In the YouTube video "How ‘Eastside’ Accidentally Turned Benny Blanco Into a Superstar" by Daniel Wall, Benny Blanco's effect rack has a API Mic Pre, which is visible underneath the Chandler TG2.

can be seen in this post from February 28, 2014

Selena Gomez is confirmed to use the API 3124+ preamp, as she is seen interacting with it at the 1:26 mark in the short film "I Said I Love You First... (Short Film)" produced by Vevo, available on the SelenaGomezVEVO YouTube channel.

Sold on Reverb.com.

From YTG: This is one of my favorite pieces of gear! 4 amazing API pre-amps in a one rack slot chassis. These pre-amps add a really nice color to whatever you send through it. Selling it because I'm upgrading to the 3124V version.

According to the "equipment list" found on Church Studios, owned by Epworth, one of the things listed is API 3124+ mic pres.

"I also have gear by Neve and Helios, UA-610 mic pres, API 3124s, the Vertigo VSM2, GML EQ, the Alan Smart C2, an old LA2A, Distressors, an Eventide H8000, and so on."