[Galaxy S 4 Mini Android Development] piskor:
There is no messaging app in 18.11 build

Here is a list of all apk files inside /system directory:

app/BasicDreams/BasicDreams.apk
app/Bluetooth/Bluetooth.apk
app/BluetoothExt/BluetoothExt.apk
app/BluetoothMidiService/BluetoothMidiService.apk
app/Browser/Browser.apk
app/Calendar/Calendar.apk
app/Camera2/Camera2.apk
app/CaptivePortalLogin/CaptivePortalLogin.apk
app/CertInstaller/CertInstaller.apk
app/CMFileManager/CMFileManager.apk
app/DeskClock/DeskClock.apk
app/Development/Development.apk
app/DocumentsUI/DocumentsUI.apk
app/DownloadProviderUi/DownloadProviderUi.apk
app/Eleven/Eleven.apk
app/Email/Email.apk
app/ExactCalculator/ExactCalculator.apk
app/Exchange2/Exchange2.apk
app/Gallery2/Gallery2.apk
app/HTMLViewer/HTMLViewer.apk
app/KeyChain/KeyChain.apk
app/LatinIME/LatinIME.apk
app/LatinImeDictionaryPack/LatinImeDictionaryPack.apk
app/LiveWallpapers/LiveWallpapers.apk
app/LiveWallpapersPicker/LiveWallpapersPicker.apk
app/LockClock/LockClock.apk
app/Microbes/Microbes.apk
app/NfcNci/NfcNci.apk
app/PacProcessor/PacProcessor.apk
app/PhotoPhase/PhotoPhase.apk
app/PicoTts/PicoTts.apk
app/PrintSpooler/PrintSpooler.apk
app/Profiles/Profiles.apk
app/Provision/Provision.apk
app/Stk/Stk.apk
app/telresources/telresources.apk
app/TimeService/TimeService.apk
app/UserDictionaryProvider/UserDictionaryProvider.apk
app/WAPPushManager/WAPPushManager.apk
app/webview/webview.apk
framework/framework-res.apk
framework/org.cyanogenmod.platform-res.apk
priv-app/AicpExtras/AicpExtras.apk
priv-app/AudioFX/AudioFX.apk
priv-app/BackupRestoreConfirmation/BackupRestoreConfirmation.apk
priv-app/CalendarProvider/CalendarProvider.apk
priv-app/CallLogBackup/CallLogBackup.apk
priv-app/CarrierConfig/CarrierConfig.apk
priv-app/CellBroadcastReceiver/CellBroadcastReceiver.apk
priv-app/CMSettingsProvider/CMSettingsProvider.apk
priv-app/Contacts/Contacts.apk
priv-app/ContactsProvider/ContactsProvider.apk
priv-app/DefaultContainerService/DefaultContainerService.apk
priv-app/Dialer/Dialer.apk
priv-app/DownloadProvider/DownloadProvider.apk
priv-app/ExternalStorageProvider/ExternalStorageProvider.apk
priv-app/FusedLocation/FusedLocation.apk
priv-app/InputDevices/InputDevices.apk
priv-app/ManagedProvisioning/ManagedProvisioning.apk
priv-app/MediaProvider/MediaProvider.apk
priv-app/MmsService/MmsService.apk
priv-app/OneTimeInitializer/OneTimeInitializer.apk
priv-app/PackageInstaller/PackageInstaller.apk
priv-app/ProxyHandler/ProxyHandler.apk
priv-app/Settings/Settings.apk
priv-app/SettingsProvider/SettingsProvider.apk
priv-app/SharedStorageBackup/SharedStorageBackup.apk
priv-app/Shell/Shell.apk
priv-app/SoundRecorder/SoundRecorder.apk
priv-app/StatementService/StatementService.apk
priv-app/SystemUI/SystemUI.apk
priv-app/Tag/Tag.apk
priv-app/Telecom/Telecom.apk
priv-app/TelephonyProvider/TelephonyProvider.apk
priv-app/TeleService/TeleService.apk
priv-app/ThemeChooser/ThemeChooser.apk
priv-app/ThemesProvider/ThemesProvider.apk
priv-app/Trebuchet/Trebuchet.apk
priv-app/VpnDialogs/VpnDialogs.apk
priv-app/WallpaperCropper/WallpaperCropper.apk

There is MmsService.apk but is not visible in the app drawer.

/edit/

apk list from /system without gapps installed