I have a bool column in DjangoAdmin which shows the red and green icons like so:
The client it's for however is requesting blue and yellow icons since it's what they've been using for years. Is there any way to replace these and use my own custom icons?
These icons are placed in STATIC_ROOT/admin/img/icon-yes.svg and STATIC_ROOT/admin/img/icon-no.svg, you can change them with your preferred ones. you can also override them in the static folder to preserve the customization for future collectstatics.
If you want to have customized icons just for a subset of users, you can have two versions of the template, the default and the customized, and then serve them to client based on their role, group, username, ... .
more information is available here: Overriding admin templates
