Calendar day display issue

This issue persists from older versions of the  IPS.
See my settings and event rendering.
For your convenience, I use English language in the image.

In versions 4.x.x I solved this issue by change mday and monthName in calendarDay template.

<h1 class='ipsType_pageTitle ipsType_center'>{lang="cal_month_day" sprintf="$date->mday, $date->monthName, $date->year"}</h1>

Now in version 5 this will not be possible.
What solution do you propose?