[BUG] `0.6.6` consistently fails to download random APKs; returns "Invalid server response".

[RokeJulianLockhart]

How To Reproduce

Attempt to download f-droid.org/repo/com.nextcloud.android.beta_20250922.apk as an update.

The Actual Behaviour

1. The GUI silently fails to initiate download:

   screen-20250926-104709.mp4

   To diagnose, within user-attachments/files/22851570/PCAPdroid_10_Oct_14_44_27.pcap.zip ^{1 2} are the network requests: ³

   IPProto,SrcIP,SrcPort,DstIp,DstPort,UID,App,PackageName,Proto,Status,Info,BytesSent,BytesRcvd,PktsSent,PktsRcvd,FirstSeen,LastSeen
   17,10.215.173.1,44596,10.215.173.2,53,10341,Droid-ify,com.looker.droidify,DNS,Closed,apt.izzysoft.de,61,109,1,1,2025-10-10T14:44:31.377+01:00,2025-10-10T14:44:31.383+01:00
   6,10.215.173.1,48246,144.76.109.58,443,10341,Droid-ify,com.looker.droidify,HTTPS,Closed,apt.izzysoft.de,1181,5223,9,8,2025-10-10T14:44:31.386+01:00,2025-10-10T14:44:31.636+01:00

2. A notification is produced:

   NotificationRecord(0x009013b3: pkg=com.looker.droidify user=UserHandle{0} id=3 tag=download-com.rk.xededitor importance=2 key=0|com.looker.droidify|3|download-com.rk.xededitor|10341: Notification(channel=downloading shortcut=null contentView=null vibrate=null sound=null defaults=0 flags=ONLY_ALERT_ONCE|AUTO_CANCEL color=0xff00ff00 vis=PRIVATE))
     uid=10341 userId=0
     opPkg=com.looker.droidify
     icon=Icon(typ=RESOURCE pkg=com.looker.droidify id=0x01080078)
     flags=ONLY_ALERT_ONCE|AUTO_CANCEL
     originalFlags=ONLY_ALERT_ONCE|AUTO_CANCEL
     pri=0
     key=0|com.looker.droidify|3|download-com.rk.xededitor|10341
     seen=false
     groupKey=0|com.looker.droidify|3|download-com.rk.xededitor|10341
     notification=
           fullscreenIntent=null
           contentIntent=PendingIntent{2cb1d70: PendingIntentRecord{a38b328 com.looker.droidify startActivity (allowlist: 75c26ba:+30s0ms/0/NOTIFICATION_SERVICE/NotificationManagerService)}}
           deleteIntent=null
           number=0
           groupAlertBehavior=0
           when=1760090738380/1760090738380
           tickerText=null
           vis=0
           contentView=null
           bigContentView=null
           headsUpContentView=null
           color=0xff00ff00
           timeout=PT0S
           extras={
               android.title=String (Couldn't download Xed-Editor)
               android.reduced.images=Boolean (true)
               android.subText=null
               android.showChronometer=Boolean (false)
               android.text=String (Invalid server response)
               android.progress=Integer (0)
               android.progressMax=Integer (0)
               android.appInfo=ApplicationInfo (ApplicationInfo{813d8e9 com.looker.droidify})
               android.showWhen=Boolean (true)
               android.largeIcon=null
               android.infoText=null
               android.progressIndeterminate=Boolean (false)
               android.remoteInputHistory=null
           }
     publicNotification=
           None
     stats=SingleNotificationStats{posttimeElapsedMs=387767886, posttimeToFirstClickMs=-1, posttimeToDismissMs=-1, airtimeCount=0, airtimeMs=0, currentAirtimeStartElapsedMs=-1, airtimeExpandedMs=0, posttimeToFirstVisibleExpansionMs=-1, currentAirtimeExpandedStartElapsedMs=-1, requestedImportance=3, naturalImportance=2, isNoisy=true}
     mContactAffinity=0.0
     mRecentlyIntrusive=false
     mPackagePriority=0
     mPackageVisibility=-1000
     mSystemImportance=UNSPECIFIED
     mAsstImportance=UNSPECIFIED
     mImportance=LOW
     mImportanceExplanation=app
     mProposedImportance=UNSPECIFIED
     mIsAppImportanceLocked=true
     mSensitiveContent=false
     mIntercept=false
     mHidden==false
     mGlobalSortKey=crtcl=0x0002:intrsv=1:grnk=0x000b:gsmry=1:nsk:rnk=0x000b
     mRankingTimeMs=1760090738380
     mCreationTimeMs=1760090738384
     mVisibleSinceMs=0
     mUpdateTimeMs=1760090738384
     mInterruptionTimeMs=1760090738592
     mSuppressedVisualEffects= 0
     mSound= content://settings/system/notification_sound
     mVibration= null
     mAttributes= AudioAttributes: usage=USAGE_NOTIFICATION content=CONTENT_TYPE_SONIFICATION flags=0x800 tags= bundle=null
     mLight= null
     mShowBadge=false
     mColorized=false
     mAllowBubble=false
     isBubble=false
     mIsInterruptive=true
     effectiveNotificationChannel=NotificationChannel{mId='downloading', mName=Downloading, mDescription=, mImportance=2, mBypassDnd=false, mLockscreenVisibility=-1000, mSound=content://settings/system/notification_sound, mLights=false, mLightColor=0, mVibrationPattern=null, mVibrationEffect=null, mUserLockedFields=0, mUserVisibleTaskShown=true, mVibrationEnabled=false, mShowBadge=false, mDeleted=false, mDeletedTimeMs=-1, mGroup='null', mAudioAttributes=AudioAttributes: usage=USAGE_NOTIFICATION content=CONTENT_TYPE_SONIFICATION flags=0x800 tags= bundle=null, mBlockableSystem=false, mAllowBubbles=-1, mImportanceLockedDefaultApp=false, mOriginalImp=2, mParent=null, mConversationId=null, mDemoted=false, mImportantConvo=false, mLastNotificationUpdateTimeMs=0}
     mAdjustments=[]
     shortcut=null found valid? false
     mUserVisOverride=-1000

The Expected Behaviour

It should download, then install.

My Environment

1. The Application Version

   versionName=0.6.6
   versionCode=660

2. The Device Model

   Fairphone 5

3. The OS And Its Version

   [ro.build.version.release]: [15]
   [ro.build.display.id]: [FP5.VT2D.C.054.20250814]

Footnotes

1. android.stackexchange.com/posts/247052/timeline#comment_356763 ↩

2. security.stackexchange.com/revisions/77092/1 ↩

3. github-linguist/linguist/issues/7630 ↩

[RokeJulianLockhart]

I was able to remediate this by downloading the update via apt.izzysoft.de/fdroid/repo/com.machiav3lli.fdroid_1107, instead.