Answer by taking a quote from the following article:

Evanescence () is an American rock band founded in Little Rock, Arkansas, in 1995 by singer/pianist Amy Lee and guitarist Ben Moody. After recording independent albums, the band released their first full-length album, Fallen, on Wind-up Records in 2003. Fallen sold more than 17 million copies worldwide and helped the band win two Grammy Awards out of seven nominations. A year later, Evanescence released their first live album, Anywhere but Home, which sold more than one million copies worldwide.

On April 27, 2015, it was announced that the band would perform at Japan's Ozzfest on November 21, 2015, as the second headline act, making it the band's first live performance since their hiatus. Prior to Ozzfest, Evanescence would play three shows in the United States. On August 7, 2015, Lee announced that long-time guitarist Terry Balsamo had departed the band. His position was filled by German singer and guitarist Jen Majura, bassist for folk metal band Equilibrium. In an October 2015 interview, Lee stated that the band would continue to tour in 2016, but that when it came to recording new music, she was focusing on recording a solo album rather than a new Evanescence album. In late 2016, the band toured select cities in the United States, choosing alternative rock band Veridia as their opener.  On September 13, 2016, the band announced a vinyl box set titled The Ultimate Collection that includes all of their albums (including Origin) and a new version of "Even in Death", a song which first appeared on Origin. The set was released on December 9, 2016. During an interview with Loudwire, Lee stated "there is Evanescence in the future" and that there had been work on another pre-Fallen song which would be released later. On February 18, 2017, a compilation album titled Lost Whispers was made available for streaming and downloading on Spotify, iTunes and Anghami. It contained the rerecorded "Even in Death", previously released B-sides, the four deluxe edition bonus tracks to Evanescence, and the new song "Lost Whispers".  On March 20, 2017, Lee spoke to AOL Build about her solo single, "Speak to Me"; during the interview, she spoke of "a new album" in the works by Evanescence, saying "We're working on something. [...] It's not just a straightforward 'next Evanescence album'," implying a stylistic change. In a March 23 interview with Metal Hammer, Lee stated that "It's something unique, something complex, something a little bit beyond that - and it's definitely new territory for all of us." The album was intended for release later in 2017.  In a Facebook post, Lee revealed that the new album is titled Synthesis. According to Lee, the album will be an orchestral piece that contains instruments such as brass and other orchestral elements. She also revealed that David Campbell, who worked on all of the band's previous albums, would return to compose for the new project. Lee said that the album is about "orchestra and electronica", and that the band is taking selected songs from their previous albums and stripping out the rock guitars and drums, rebuilding them into a classical arrangement reminiscent of a soundtrack. The album will also contain two new original songs. The first recording session for Synthesis took place on May 23, 2017, and a remake of "Bring Me To Life" was released as a single on August 18. On August 15, the band announced that recording Synthesis was in its final stages. Evanescence will be touring with a full orchestra in late 2017 in support of the album, and tickets will be sold starting on August 18. The band will later be touring across the US. Each ticket purchased comes with a digital copy of Synthesis after its release. On September 14, 2017, the single "Imperfection" was officially released.

What did the group do in 2015*?
On April 27, 2015, it was announced that the band would perform at Japan's Ozzfest on November 21, 2015,