Edit HTML Master Pages After SharePoint Designer 2013 Retirement

[RocioA]

I am curious what the guidance is for editing HTML custom master pages on classic SharePoint sites in M365 when SharePoint Designer 2013 end of support date approaches in 2026? Will the app still function?

[#2]

The recommendation is to go to modern as soon as possible. At some point classic experiences are going to fall under end of support

[#3]

Thanks for the tip. Any recommendations to display XML data or RSS feeds on modern sites?