there are two new features for particles :
<isDaylightAffected value="false"/>
<particleSystemStartDelay value="0" />
description is here at the end of the list:
https://docs.megaglest.org/XML/Unit_Particle#Elements_of_particlesisDaylightAffectedIf set to true, the tilesets day/night light coloring of the current moment affects the particle colors ( meant to be used with mode "black" ). By this the coloring of the particles fits to the daytime. By default it's set to false. ( this is good for dust of walking or moving units and fog , make it look much better in the night )
particleSystemStartDelayThis delays the start by the given number of particle system update cycles (integer). Default is 0.