[4] On 24 June, Željezničar and Siniša Stevanović negotiated a two-year contract extension lasting until May 2021.

[5] On 25 June, Željezničar announced the signing of 18-year-old Amar Mehić from Zvijezda Gradačac.

[7] On 27 June, Željezničar signed a sponsorship agreement with Tondach Wienerbeger and Sarajevo Business Consulting.

[8][9] On 27 June, Željezničar announced the signing of 21-year-old Petar Bojo from Mladost Doboj Kakanj.

[14] On 8 July, Željezničar announced the signing of 18-year-old Sedad Subašić from Rudar Kakanj.

[23] On 30 July, Željezničar and Rail Cargo Logistics – BH osiguranje extended their sponsorship agreement.

[27] On 24 October, Željezničar signed a sponsorship agreement with Exclusive Change (EXC).

[34] On 17 December, Željezničar and Umm Salal completed the transfer of Enes Sipović.

[35] On 20 December, Željezničar signed a 5 year sponsorship agreement with Italian sportswear company Macron.

[36] On 3 January, Željezničar and Suwon Samsung Bluewings completed the transfer of Sulejman Krpić.

[38] On 12 January, Željezničar announced Haris Hajdarević will be leaving on loan to Sloboda Tuzla.

[41] On 30 January, Željezničar and Mladen Veselinović negotiated a two-and-a-half-year contract extension lasting until June 2022.

[43] On 14 February, Željezničar announced the signings of 33-year-old Nermin Jamak and 25-year-old Luka Miletić.