From: mariasophia@comprehension.com   
      
   Martin Schöön wrote:   
   >> Most likely cause in your case you may have had an older OpenContacts build   
   >> perhaps, or a fork perhaps, or maybe even a version installed from   
   >> somewhere other than F-Droid perhaps as in *those* cases, F-Droid will   
   >> refused to overwrite it because the signing keys won't match.   
   >>   
   > No, never tried OpenContacts before.   
      
   Hi Martin,   
      
   You have plenty of options.   
      
   I did helpfully provide TWO different APK sources (Gitlab & F-Droid).   
   Did you try both of them? That's what I would have done.   
      
   It's likely the Gitlab APK will work even if the F-droid failed for you.   
   I's what most people do when they have the problem that you reported.   
      
   That's why I put links to both of them in the OP for example.   
   I wouldn't just give up when the first stumbling block hits me.   
      
   However, I didn't experience the signature mismatch you're reporting,   
   and I have over a thousand apps (many of which are contacts related).   
      
   I have between 60 and 70 packages alone that read contacts, but none of   
   them clashed with DOpen Contacts when I installed it on Android 13.   
      
   When I opened DOpen Contacts in Muntashirakon App Manager (which everyone   
   by now has because it's 1 of the best Android apps ever written), it shows   
    Verified   
    Signature schemes: v1, v2   
    Signer Certificate   
    Subject: C=US,O=Android,CN=Android Debug   
    Issuer: C=US,O=Android,CN=Android Debug   
    Issued date: Fri Mar 24 11:11:12 PDT 2017   
    Expiry date: Sun Mar 17 10:11:12 PST 2047   
    Type: X.509, Version: 1, Validity: Valid   
    Serial number: 01   
    Checksums   
    MD5: faab441b6a45efa6bf9c5ff5044d42f5   
    SHA-1: cf9157b36895569cc2da9b410fefd19d1cbc65ab   
    SHA-256: 30c07613a1420ec5d83006d763fa4d5aa4f29d193942f7e922573f8fd623e5c6   
    SHA-384: 08e8862543982fe487e768c7829c5b287f9c59e7f9b05a7e14a3e9   
   f54da6444040e433087bf2d55adf2785ff2e6e85a   
    SHA-512: e12b9b83c5729bc8feaacc5e623557d5eb51fe840f9d200b7e01d2   
   4efa34188df6c87866b960a21acb43eec1bc270b7168674b54b7df939ba7979acbb94f0fc   
    Signature   
    Algorithm: SHA1withRSA   
    OID: 1.2.840.113549.1.1.5   
    Signature: 1cbbc23247d9823ebd725498663e0ae3c4b6ccb23094acb44a5f   
   4521e4ef3b9440ed1fab8820cafca585058ab02a25ecd0f889e004f90a09e004   
   c5be8aba2bc3daadf24332ab344486051771c157caebb19c4edebdc54c765564   
   06cde3bec7245b3ddf7fb0f6eaa01563fbd39dff5824c9231af437eb89af   
   5542341dbe067   
    Public key   
    Algorithm: RSA   
    Format: X.509   
     Exponent: 65537   
    Modulus: 00a40404d368daadb36d1e5dbfe7cca948c10fe34eb4020906eadb   
   86d1681a74b7e5124309717799bab6bce38f7ddbbc8770e1d049f0c3e8b8f623   
   f4ae7d8f775d506825166897125ffb2b573f63c09ffa7b9dcf95866eafcea9a0   
   b9b29515c8582fe1af38b58aee23f0bac7945e78a97c769acc89e476c938   
   4b9b9e5da337   
      
   You can't do that perhaps because it may not have actually   
   installed itself, but you can certainly look at the APK.   
      
   I just examined the F-Droid APK using MixExplorer which brings up   
   Muntashirakon which reveals the following information about it.   
    opencontacts.open.com.opencontacts   
    Version: 31.0 | 31   
    Installed: 28.0 | 28   
    Open App   
    Target: X.0 (X, API 32)   
    Minimum: 4.1 (JB, API 16)   
    Play Store		Manifest		Certificate   
      
   Clicking on the Certificate link in that GUI reveals   
    Type: X.509   
    Version: 3   
    Serial Number: 0x7bb18041   
    Subject: CN=FDroid, OU=FDroid, O=fdroid.org, L=ORG, ST=ORG, C=UK   
    Valid from: Oct 27, 2018 11:56 AM   
    Valid until: Mar 14, 2046 10:56 AM   
    Signature   
    Algorithm: SHA256withRSA   
    OID: 1.2.840.113549.1.1.11   
    Public Key   
    Algorithm: RSA (2048 bits)   
    Exponent: 65537   
      
   When I check the CHECKSUM by clicking on the link, I get:   
    CRC32: 03366234   
    MD5: 7ba54b67b1a2cea0396ab533ae731807   
    SHA1: efa927efe8218e143bf8ef5e8d8c33d7dbda5792   
    SHA256: b9ab2d7861cd40b98ca41a1fe0aa220d53135829ffeaf6b6c64b3b36b2df9505   
    SHA384: b8469130a823813560b5e404ed024e8d3ffd3b96400856d67c6a537   
   10f03cefcba0e14535e4a9eb43ec38d3367304a3   
    SHA512: 107121542beb30e84208790edd234d981127113511e6f5b1a846eba   
   471eac7b3dfbe19d933faa4d804b0a07ac9a845d83dd53b9271f4914012482faef43c48b   
    Modules: 197128540709971589694584707855060469431172712639758750   
   7738127533430811404862317137489721357824602046245116439141943382   
   8296619271355898243734739906591448598665399094555085005472702287   
   842200775980867902114961996605864421217999673029368833190953   
   5412388640606350473057085243765293712967275900766874033235534472   
   5799215977619017363694039235924568092445310292045384134180759195   
   3096347257375714559466950004589432835224400097660424682094672826   
   773028437452712205895377613806096156446673821600774533503782   
   5948743163612249862793750542174507340085898882761438980499292400   
   8018380539356526298057098572766426945143487600077317   
    CRC32: 03366234   
    MD5: 7ba54b67b1a2cea0396ab533ae731807   
    SHA1: efa927efe8218e143bf8ef5e8d8c33d7dbda5792   
    SHA256: b9ab2d7861cd40b98ca41a1fe0aa220d53135829ffeaf6b6c64b3b36b2df9505   
    SHA384: b8469130a823813560b5e404ed024e8d3ffd3b96400856d67c6a537   
   10f03cefcba0e14535e4a9eb43ec38d3367304a3   
    SHA512: 107121542beb30e84208790edd234d981127113511e6f5b1a846eba   
   471eac7b3dfbe19d933faa4d804b0a07ac9a845d83dd53b9271f4914012482faef43c48b   
      
   Do you get the same output from the F-Droid APK you downloaded?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)