id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
23021	Last-Modified header always set to 1970... when it is blank. Make browser cannot refresh cache.	slene	ryan	"In #22258, the Last-Modified header set blank when user login.

A response with a blank Last-Modified header will be set to ""Thu, 01 Jan 1970 00:00:00 GMT"" in some server. The browser will be always send a If-Modified-Since header ""Thu, 01 Jan 1970 00:00:00 GMT"". and the server response a 304 status code. Make the browser can not refresh cache.

In php5.2 the Last-Modified header always blank. But php5.3 has header_remove remove it. 
The Last-Modified header should be remove form $headers array when it blank.

sorry my bad english..."	defect (bug)	closed	normal	3.5.1	General	3.5	normal	fixed	has-patch commit fixed-major	slene