If you do download iReport 4.0.1 from third-party sites (not Jaspersoft/SourceForge), – abandonware is sometimes repackaged with malware.
Obtain iReport-5.6.0-windows-installer.exe from an official source. jaspersoft ireport designer 401 download free
Go to Tools > Options > Fonts to install and export your TrueType Fonts (TTF) as a font extension jar. Migrating from iReport 4.0.1 to Jaspersoft Studio If you do download iReport 4
If you are starting a new project, it is highly recommended to use the modern Jaspersoft Studio. If you are trying to upgrade a legacy project, let me know: What specific errors are you seeing? Are you migrating to a newer JasperReports library? Migrating from iReport 4
Jaspersoft Studio can open, edit, compile, and save older .jrxml files created in iReport 4.0.1.
Functional but Obsolete – Only for Legacy Maintenance
It runs on Windows (XP through 10), Linux, and macOS, provided the correct Java environment is configured.