This is the fourth edition of the conference "Advances in Qualitative Theory of Differential Equations" and it will take place in Soller. The first and third editions were in Castro Urdiales and the second in Tarragona. See more information of them in AQTDE2011, AQTDE2015, and AQTDE20219.

The main objective of this conference is to show the recent developments in qualitative theory of differential equations, especially in low dimension, and their applications to different branches of science. Thus, lectures will be devoted to current topics in bifurcation theory, Abelian integrals, control on the number of periodic orbits, Hilbert 16th problem, oscillations of the time function, Abel equations, integrability and related topics.

It is planned the participation of around 50 researchers. The event aims to create a relaxed atmosphere, with few lectures and free time between them for fruitful discussions.