doc/sphinx/whats-new/upgrading-7.4.rst
.. _whatsnew_upgrading_7.4:
%%%%%%%%%%%%%%%%%%%%%%%% Upgrading to Varnish 7.4 %%%%%%%%%%%%%%%%%%%%%%%%
When upgrading from Varnish-Cache 7.3, there is only one breaking change to consider in VCL:
The Content-Length and Transfer-Encoding headers are now
protected, they can neither be changed nor unset. This change was
implemented to avoid de-sync issues from accidental, inadequate
modifications of these headers.
For the common use case of unset (be)req.http.Content-Length to
dismiss a request body, unset (be)req.body should be used.
The new varnishd parameter startup_timeout now specifically
replaces cli_timeout for the initial startup only. In cases where
cli_timeout was increased specifically to accommodate long startup
times (e.g. for storage engine initialization), startup_timeout
should be used.
eof