Any release of a person from a covenant by virtue of this Act does not affect any liability of his arising from a breach of the covenant occurring before the release.
Where—
then, as from the release of the tenant, that other person is released from the covenant mentioned in paragraph (b) to the same extent as the tenant is released from that tenant covenant.
Where a person bound by a landlord or tenant covenant of a tenancy—
the assignment does not affect any liability of his arising from a breach of the covenant occurring before the assignment.
Where by virtue of this Act a person ceases to be entitled to the benefit of a covenant, this does not affect any rights of his arising from a breach of the covenant occurring before he ceases to be so entitled.