In Spring 2013, Kalvis and Mārtiņš started recording STandART’s 3rd album as a duo – this time in Jūrmala with Sandris Savickis (Starring Two). At the end of summer, STandART played two concerts with a live drummer Edgars Liljē (Marta Migla, ex-Pasaules Gaisma, ex-Depo) – at Menuo Juodaragis festival in Lithuania and Marta Migla birthday party at Depo, Riga.
Afterwards, Kalvis and Mārtiņš focused on studio work. In early 2015, the mixing of the album was started with Kaspars Tobis again (Dzelzs Vilks, 7 Synths). After 2.5 years spent recording, a new single Fever (Drudzis) was realeased in September 2015 followed by Under The Cat-Fur-Coloured Sky (Zem Kaķa Spalvas Krāsas Debesīm) and Midsummer Fires (Jāņugunis) in 2016 and Runes (Rūnas) in 2017. Latvian versions of all singles were widely played on Radio NABA. At the beginning of 2017, Kalvis Kluburs and Sandris Savickis completed two remixes under STandART name for the Estonian band Forgotten Sunrise (their single Dusturn was published in April 2017).
Finally, after 4 years of studio work, STandART’s 3rd album Jūrasputnu Mistērijas: Mysteries Of The Seabirds was released in June 2017 via Naba Music / Melo Records. The first concerts since 2013 were played as a duo, but at the Laba Daba 2017 festival STandART played as a five-people team, including Jānis Traviņš (Marta Migla) and on individual songs – Vladislavs Beļskis and Signe Ābola.
Later that year, Jānis Traviņš permanently joined STandART, and the band performed live at Radio Naba birthday broadcast in December. In early 2018, STandART band published another single – Kolka – from the album Jūrasputnu Mistērijas: Mysteries Of The Seabirds.