o_e_l_e_o is correct... it's a mechanism used to try and keep the mempool "size" to below 300 Megabytes... Transactions with very very low fees will either not be accepted or be "purged" if the "mempoolminfee" increases to a value higher than the transaction.
If you look here: https://statoshi.info:3000/d/000000020/memory-pool?orgId=1 (check last graph)
and here: https://mempool.space/
You'll see that this value is currently around 7 sats/byte... any transaction with a fee less than this will either not be accepted... or purged if it was already in a node's mempool.
Note that this value is not the same as the "minrelaytxfee" (which usually defaults to 1 sat/byte)
If you look here: https://statoshi.info:3000/d/000000020/memory-pool?orgId=1 (check last graph)
and here: https://mempool.space/
You'll see that this value is currently around 7 sats/byte... any transaction with a fee less than this will either not be accepted... or purged if it was already in a node's mempool.
Note that this value is not the same as the "minrelaytxfee" (which usually defaults to 1 sat/byte)