I have been testing SharePoint 2019 and I have a question related to Modern User Interface PDF Viewer Configurations.
On my SharePoint 2019 On-Premise environment, I have Office Web Apps Configured but we don’t want to Open PDF in the Office Web-App, we want to open it in the Client Application.
In the previous SharePoint versions, I used the commands below:
• Get-SPWOPIBinding –Application "WordPDF" | Remove-SPWOPIBinding -Confirm:$false
• Did an IIS reset.
• Cleared browser Cache.
The PDF opened in Client Application for SharePoint Classic User Interface but in Modern User Interface it opens in default PDF Viewer(screenshot below).
Open Documents in Client Applications by Default
feature in site collection and check ( Site collection settings > Site collection features)