As you can see from three screenshots above (Orders, Order Details, and Customers pages), the Pager styles are NOT implementing from v2026’s Pager style.
Open the project by v2025, default option in Paging section style is NextPrev,
Change the option to NumericPage, save the project by v2025, then close the project,
Open the .pmp file by Notepad++, check the setting now is PagerStyle="1" (as expected),
Open that project by v2026, check the Pager proximity, it is 0. Shouldn’t it be automatically converted to PagerStyle="2", according to the behavior in v2026 as you mentioned above?
Since the default behavior for Pager proximity is always 0, then there is no global setting PagerStyle in the project file added, thus this will cause the issue as I mentioned above.
This is probably a conversion issue. You’d better report to the support email. In the mean time, just manually change the Pager proximity setting to “2”.