MuseScore 3 doesn't import jumps from MuseScore 1
MuseScore 3(.1) doesn't import jumps from MuseScore 1(.3), instead it loses them completly
Try the attached score, coda-1.x.mscx, created in MuseScore 1.3, with a Segno, a To Coda, a D.S. al Coda and a Coda.
None of these show in MuseScore3.
All show in MuseScore 2(.3.2), but when saved there and importing the result into MuseScore 3, there are still issues, check the attachet score, coda-1.x-2.x.mscx, the Segno and the Coda symbols are wrong, an Fb resp. F notehead.
This pretty much removes a possible workaround of importing a 1.x score into 2.x first and then to 3.x
Such a score, coda-2.x.mscx, created in MuseScore2(.3.2) from scratch imports cleanly in MuseScore 3(.1).