diff --git a/installer/installer.iss b/installer/installer.iss
index 00e999e..334912f 100644
--- a/installer/installer.iss
+++ b/installer/installer.iss
@@ -22,8 +22,11 @@ Compression=lzma2
 SolidCompression=yes
 WizardStyle=modern
 PrivilegesRequired=admin
-ArchitecturesAllowed=x64compatible
-ArchitecturesInstallIn64BitMode=x64compatible
+; "x64compatible" is Inno Setup 6.3+ syntax. Our CI uses 6.2.2 (last
+; version still parsed by innoextract 1.9 in Debian trixie), so use
+; the legacy "x64" keyword which works on 6.0 through 6.7.
+ArchitecturesAllowed=x64
+ArchitecturesInstallIn64BitMode=x64
 LicenseFile=..\LICENSE
 MinVersion=10.0.17763
 UninstallDisplayName=Drover-Go {#MyAppVersion}