This might be common in all versions. I didn't notice it before upgrade.
example pages:
http://technopolis.ir/category/articles/security-articles/backtrack/
is fine, but below link returns 404 error
http://technopolis.ir/category/articles/security-articles/backtrack/page/2
this also goes for:
http://technopolis.ir/category/articles/
All pages are fine but last one.
I tried deleting .htaccess and regenerating it, I tried disabling all plugins,I tried every suggestion on wordpress codex about permalink.
nothing works.
today I tried default permalinks. even it didn't work.
http://technopolis.ir/?cat=4&paged=3 and all pages before nimber 3 are fine.
http://technopolis.ir/?cat=4&paged=4 but this page(last one) causes error.
Can my theme be the cause of this problem?
or it is a WP core error?
please help me.