Publishing an app update whose ZIP contained a Windows executable (
.exe /
.dll) could fail — either with a generic
"Server returned invalid response", or with
"ZIP contains blocked file type".
Two separate causes, both fixed:
- Firewall false positive — our edge firewall content-inspects request bodies and was blocking API uploads that carried real binaries. API endpoints are now excluded from that inspection.
- Over-strict ZIP validation — the server-side check rejected any archive containing
.exe, .dll or client script files. Update packages are stored and delivered to your users exactly as uploaded — never executed on our servers — so the check now only blocks server-executable scripts (.php and friends), which is the actual threat it was built for.
Verified end-to-end: a real update ZIP with an
.exe payload now publishes and reaches devices normally.
Thanks to the developer who reported it — diagnosed, fixed and verified the same day. If an update upload ever fails for you,
open a ticket and include the exact error text.