ZIP 2003 states that the Zcash NU7 network upgrade at block height 3,543,405 will disable version 4 transactions, rendering unmigrated funds in the Sprout privacy pool unspendable

From the articleZcash is about to freeze $16 million in its oldest privacy poolAlso in Zcash to freeze $16M in its oldest privacy pool with NU7 upgrade
Opening sign-in…