I try upgrading OTRS from 5.0.23 to 6.0.1.
I upgraded using the OTRS rpm package.
After that I updated GeneralCatalog and ITSM Core in use orm files.

However, after upgrading using the "ITSMIncidentProblemManagement - 6.0.1.opm" file,
an attempt to see the article results in an error.
(Internal Server Error)
And all articles doesn't open.

- Error log(/var/log/httpd/error_log)
[:error] [pid XXXXX] Can't locate object method "ArticleContentIndex" via package "Kernel::System::Ticket" at /opt/otrs//Kernel/Modules/AgentTicketZoom.pm line 711.
# cat -n /opt/otrs//Kernel/Modules/AgentTicketZoom.pm
:
703 # Get all articles.
704 my @ArticleContentArgsAll = (
705 TicketID => $Self->{TicketID},
706 StripPlainBodyAsAttachment => $Self->{StripPlainBodyAsAttachment},
707 UserID => $Self->{UserID},
708 Order => $Order,
709 DynamicFields => 0, # fetch later only for the article(s) to display
710 );
711 my @ArticleBoxAll = $TicketObject->ArticleContentIndex(@ArticleContentArgsAll);
:
Articles can be seen before installing ITSMIncidentProblemManagement.

Why can't view articles?
Thanks always support.