Set theory
v8.5.4 · 20.7 MB · code 805040
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File information
UpdatedFeb 22, 2026
PublishedApr 20, 2021
Packagecom.do_apps.catalog_728
Versionv8.5.4 (805040)
Size20.7 MB
MD590fbf77251ac13183a6db4d54b1f52fc
Min SDK19
Malware scanTRUSTED
Signature SHA197:C0:90:78:45:8E:B0:1D:0D:1D:75:E5:0F:68:C1:E2:65:85:BF:D1
SignerCN=Kirill Sidorov, C=RU
Total downloads50,000
This version50,000
DeveloperKirill Sidorov
Age ratingEveryone
What's new in v8.5.4
Various minor fixes
Security scan
TRUSTED
- Developer signature verified 2026-02-22
- Signature SHA1 97:C0:90:78:45:8E:B0:1D:0D:1D:75:E5:0F:68:C1:E2:65:85:BF:D1
- File MD5 90fbf77251ac13183a6db4d54b1f52fc
How to install Set theory v8.5.4 on Android 4.4 KitKat+
Takes about 2 minutes. You'll need roughly 20.7 MB of free storage.
- Grab com.do_apps.catalog_728_805040.apk — hit the Download button above (20.7 MB). If your browser warns about APK files, choose Keep or Download anyway — that warning fires on every APK, not just this one.
- Trust your browser to install — on Android 8+ go to Settings → Apps → Special access → Install unknown apps, pick the app you downloaded with (Chrome, Firefox, Files, etc.), and flip Allow from this source. On older Android, toggle Unknown sources under Security.
- (Optional) Verify the file — compute the MD5 of the downloaded APK and make sure it matches 90fbf77251ac1318…. Any difference means the file is corrupted or tampered — delete and re-download.
- Open the APK — tap the download notification, or find com.do_apps.catalog_728_805040.apk in your Files app under Downloads, then tap it. Android's package installer will appear.
- Check the signer — the install screen will name the publisher. For this build it should read CN=Kirill Sidorov, C=RU. If it doesn't match, cancel — you have the wrong file.
- Review permissions & tap Install — scroll the permission list, then confirm. If Play Protect flags it, tap Install anyway (this APK was scanned as TRUSTED).
- Done — open Set theory — tap Open on the install screen, or find the Set theory icon in your app drawer.
Common install errors for Set theory
- "App not installed" — usually means an older or differently-signed version is already on your device. Uninstall it first, then retry. Your data may be lost unless you back it up.
- "Parse error" — the APK is for a newer Android than yours. This version needs Android 4.4 KitKat or later. Pick an older build from the versions list below.
- "There was a problem parsing the package" — the download was interrupted. Delete the file and re-download over Wi-Fi.