The Leopard dates to 1979...but these are upgraded/modern versions.
Though hardly “next gen”
Update...
Besides the Polish which are likely older A4 versions, the Germans have now agreed to send tanks as well.
These are Leo2A6 (newer tanks albeit not the latest A7V). It appears Germany is sending 10 tanks and there is footage of them already on rail and on their way.
Sweden is also considering sending 8 Leo2’s.
So it appears Ukraine will get them after all, although in small numbers.