Landlord following old writer's public correspondence (4,6)
I believe the answer is:
open letter
'public correspondence' is the definition.
'open letter' can be an answer for 'correspondence' (I've seen this before). I am not sure about the 'public' bit.
'landlord following old writer's' is the wordplay.
'landlord' becomes 'letter' (landlords let property).
'following' says to put letters next to each other.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'writer' becomes 'pen' (something which writes).
'o'+'pen'='open'
'letter' after 'open' is 'OPEN-LETTER'.
Can you help me to learn more?
(Other definitions for open letter that I've seen before include "Communication intended for public reading" , "No confidential correspondence" , "Written missive intended for general consumption" , "Use knife, perhaps" , "public protest" .)