ESRI will be updating ArcGIS Online on November 9th. Some update highlights include:

• Map Viewer Enhancements
  • Greater support for feature aggregation
  • Enhanced visualization in heat maps
  • New and enhanced editor for Arcade expressions
  • Greater visibility, customization, and control of hatch fills
  • Support for uploading PNG, GIF, SVG, or JPEG files as custom symbols
• Improvements to Administrative Workflows
  • Visibility of last viewed date in the administrator’s item report
  • Ability to specify a default set of member categories for new members
• ArcGIS Instant Apps
  • Support for exporting data as a CSV file in Sidebar
  • Animation of two or more numeric fields in Slider
• Deprecations and Retirements
  • ArcGIS Dashboards Classic
  • Legacy Home Page in ArcGIS Online
  • Presentation for Map Viewer Classic
  • Minimalist Template in ArcGIS Instant Apps

For more information on the update, visit their posting about it here.