The 039 family (Song) is an evolution of the Kilo-class.
They're still messing around with Stirling-based AIPs which as a basic technology is something that PN had for a long time in the form of the MESMA on Agosta-90B. There's no Fuel Cells or LIBs coming so there isn't any technological leap being achieved as far the AIP or Battery solution is concerned.
No flank array sonars either (which Scorpene has) so no real improvement in active/passive sonar coverage compared to legacy Kilo.
The threat is in the fact that PN is gonna be getting 8 new boats. But the sub itself is nothing special - doesn't bring anything new to the table that makes it better than what IN has already got*, Scorpene is still technologically a superior platform.
*with the exception of AIP, but then PN already had that advantage even before Hangor came so that's not something new we need to be worried about.
