In a call for the presentation of the “Warm Up” initiative, the name attributed to the six week cycle of musical programming, the municipality advances that the preliminary event will take place between 16 and 22 August, anticipating and "warming up musically" the edition of 2021 of the Book Fair, whose news will be revealed on Friday, World Book Day. "WARM UP is the alternative proposed to open the Gardens of the Crystal Palace and, through words and music, host festivals and activities that could not be carried out in the current context", points out the council in the call. The event, he adds, "is an optimistic encouragement that the Municipality of Porto provides to cultural structures, artists and their audiences, giving them back space for activity and reinforcing their importance in the dynamics of the city".

In 2020, the Porto Book Fair, which took place in a pandemic context and with limited entries, received around 100 thousand visitors, revealed the Mayor of Porto, the independent Rui Moreira, on the last day of the literary festival that took place between 28 August and 13 September. At the time, the mayor announced that the 2021 edition would honor the writer from Porto, Júlio Dinis.

The 2020 edition of the literary festival paid tribute to the immunologist Maria de Sousa (1939-2020), who died in April, victim of infection caused by the new coronavirus, and the poet Leonor de Almeida (1909-1983). With the motto "Joy until the End of the World", a verse by writer Andreia C. Faria, the initiative's resident author, the seventh edition of the event was attended by 120 pavilions and 80 entities, with access to the state grounds limited to 3,500 people.