According to the latest post by @delpotrojuan he has not only recovered after the injury at the end of the last season, but we can also see him hitting with a new racket. It appears to be the RF97 mould, but can’t say for sure for now. He no longer has any lead at 3&9 with this racket as can be seen comparing the top and bottom(with the old racket) pictures.
On the other hand Dimitrov has been with his new racket since the end of last season and his racket is confirmed to be the RF97 variaton.
Looks like Del Potro and Dimitrov both want some of that Roger Federer magic for the new season. It Will be interesting to see them both at the @australianopen 2019.