Modern Music Festival is a joint national final system, usually hosted by Grolskira and featuring two more nations. The main theme of this national final is to enter songs from 2010's decade - that's how it earned the "modern" in the title.
Usual structure of every edition of this competition:
3 nations participate, with Grolskira (the host) among them
Every nation sends in 4 songs, so they could get in 12 songs in total
All Internatian and Outernatian nations are welcome to vote by ranking all the songs in their liking order
Participating nations in the national final must vote too, but only for the other acts
Highest scoring entries from each country win the rights to represent a nation in ISC that the edition is dedicated for
Once in a while there were twists in presenting everything. The 3rd edition of MMF had the theme slightly altered to have 2000's songs in it. And every edition there was a nation who would send their winner of the NF for the earlier edition to one edition after. The first edition it happened to Kaledonii, second - Porielana, third - Grolskira, fourth - Luzze. As well as the third edition had the first time when at least one winner of it didn't qualify. Also, the host nation ended up ranked 3rd out of all respective winners in every edition (except the 4th one).
The first edition launched in April 2015, to determine entries for ISC 35 in Madakia, Tikata. The first guests of the NF were Alteus and Kaledonii. The host cities were determined to be three, to match the spirit of the participating nation, and they ended up on the NF's title.
The first edition seemed to be a success, so there was a continuation of this national final which launched in May 2015 to determine entries for ISC 36 in Tlahuilco, Tonallán. The guests this time were Kaeros Islands and Porielana. The host city for this edition ended up to be Fapliken, Grolskira. The theme was determined for this edition to be pop and rock music.
The third edition launched in October 2015 to determine entries for ISC 41 in Nolvena, Grolskira. The guests this time were Alteus and Auspikitan. The host city for the NF also became Nolvena. The theme was both 10's and 00's songs. Grolskira had to move their winner to next edition because of already choosing their entry internally because of it being the host entry. This was the first time at least one of the NF winners didn't qualify in ISC. The hosts of the NF blamed low voting figures for it.
The fourth edition of Modern Music Festival was launched on December 2017 to determine entries for ISC 67 in Zaun, Noxus. The guests for this one were nations ruled by female players - Luzze and Spinachia. This particular edition did not have a proper host city so it ended up being hosted by the Grolskiric nation itself.
Kaledonii, second - 
Porielana, third - 
Grolskira, fourth - 
Luzze. As well as the third edition had the first time when at least one winner of it didn't qualify. Also, the host nation ended up ranked 3rd out of all respective winners in every edition (except the 4th one).
Alteus and 
Kaeros Islands and 
Auspikitan. The host city for the NF also became Nolvena. The theme was both 10's and 00's songs. Grolskira had to move their winner to next edition because of already choosing their entry internally because of it being the host entry. This was the first time at least one of the NF winners didn't qualify in ISC. The hosts of the NF blamed low voting figures for it.
Spinachia. This particular edition did not have a proper host city so it ended up being hosted by the Grolskiric nation itself.