Duplicate Entries need to be Deleted after checking Date

HI
I hope an easy Question:
My XL sheet has Duplicate entries what i need "Prune" according to the Latest EXPiry Date.
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The Sheet is sorted by KNUMBER.
After an update from another File.It happens that there are multiple entries (every Week)!

I need to DELETE these entries from this sheet (the MASTER)
Any KNUMBER (Customer Number)that has a LATER EXP(iry) Date Remains
Can anyone help me with this..
I attach the Small file .
Many thanks in Advance