IIR filters missing after opening v4.7.0 project in FIR Designer v4.7.1 (macOS)

[andrew.poulain@dolby.com]

andrew.poulain@dolby.com

29 August 2026 at 4:00 am #501354

Summary
After upgrading FIR Designer from v4.7.0 to v4.7.1, previously saved projects that were last edited in v4.7.0 no longer contain their configured IIR filters when opened in v4.7.1.
Steps to Reproduce
1 Upgrade FIR Designer from v4.7.0 to v4.7.1.
2 Open an existing project that was last saved and edited using v4.7.0.
3 Navigate to the IIR Filters tab.
Expected Result
All previously configured IIR filters should be present and unchanged.
Actual Result
The IIR Filters tab appears empty and all previously configured IIR filters are missing from the project.
Additional Testing
• Opened a separate project containing IIR filters that was originally created and last modified using a v4.6.x release.
• In this case, all IIR filters were present and displayed correctly.
• The issue appears to be specific to projects saved with v4.7.0 and then opened with v4.7.1.
Environment
• Hardware: Apple Silicon (M-Series Mac)
• Operating System: macOS 26.5.2
• FIR Designer: Upgraded from v4.7.0 to v4.7.1
Impact
Projects created or modified in v4.7.0 may lose visibility of configured IIR filters when opened in v4.7.1, potentially requiring recreation of filter settings and raising concerns about project compatibility between versions.