So I upgraded my wallet to latest litecoin core with a legacy (not HD) wallet.dat that I have been using since 2012, Tried to create MWEB address and it gives the following error.
But there is no way to upgrade the wallet.dat that i could find? (IIRC there use be an upgrade command present in older versions but it must have been removed at some point?)
Creating a new wallet that is HD and its works perfectly, but the legacy wallet.dat also will not allow to send to MWEB address and will show this error
As a workaround i created new segwit addresses in the a new HD wallet.dat and from there i could then send to MWEB addresses.
Its not a big problem for individual as we can just create a new wallet that will work with MWEB and sweep our old wallet.dats, but for exchanges that are still using older wallet.dats this will be a problem and prevent them offering withdrawal to MWEB addresses for their users.