Index: app/src/main/kotlin/at/bitfire/davdroid/sync/CalendarSyncManager.kt
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
diff --git a/app/src/main/kotlin/at/bitfire/davdroid/sync/CalendarSyncManager.kt b/app/src/main/kotlin/at/bitfire/davdroid/sync/CalendarSyncManager.kt
--- a/app/src/main/kotlin/at/bitfire/davdroid/sync/CalendarSyncManager.kt	(revision f69533b0497e71f0b817af72ec10d1f8830b060a)
+++ b/app/src/main/kotlin/at/bitfire/davdroid/sync/CalendarSyncManager.kt	(date 1730531313263)
@@ -41,9 +41,11 @@
 import java.io.ByteArrayOutputStream
 import java.io.Reader
 import java.io.StringReader
+import java.nio.charset.Charset
 import java.time.Duration
 import java.time.ZonedDateTime
 import java.util.logging.Level
+import java.util.regex.Pattern
 
 /**
  * Synchronization manager for CalDAV collections; handles events (VEVENT).
@@ -237,9 +239,11 @@
 
     override fun postProcess() {}
 
+    val regex =
+        "\\s*data:(?:[a-z]+\\/[a-z0-9\\-+.]+(?:;[a-z-]+=[a-z0-9-]+)?)?(?:;base64)?,([a-z0-9!$&',()*+;=\\-._~:@/?%\\s]*)\\s*"
+    val pattern = Pattern.compile(regex, Pattern.CASE_INSENSITIVE)
 
     // helpers
-
     private fun processVEvent(fileName: String, eTag: String, scheduleTag: String?, reader: Reader) {
         val events: List<Event>
         try {
@@ -250,9 +254,32 @@
             return
         }
 
+
+
         if (events.size == 1) {
             val event = events.first()
 
+            val description = event.description?.toByteArray()
+            if(description != null &&  description.size > 500 * 1024){
+
+                val msg = context.getString(R.string.sync_description_size_limit_msg)
+
+                val matcher = pattern.matcher(event.description.toString())
+                var newDescription = matcher.replaceAll("\n\n--- $msg ---\n\n")
+
+                val newDescriptionSize = newDescription.toByteArray().size
+                if(newDescriptionSize > 500 * 1024) {
+                    val endMsg = "\n\n--- $msg ---"
+                    newDescription = description
+                        .copyOfRange(0, 500 * 1024 - endMsg.toByteArray().size - 1)
+                        .toString(charset = Charset.defaultCharset()) + endMsg
+                }
+
+                event.description = newDescription
+
+            }
+
+
             // set default reminder for non-full-day events, if requested
             val defaultAlarmMinBefore = accountSettings.getDefaultAlarm()
             if (defaultAlarmMinBefore != null && DateUtils.isDateTime(event.dtStart) && event.alarms.isEmpty()) {
@@ -267,11 +294,13 @@
 
             // update local event, if it exists
             val local = localCollection.findByName(fileName)
+
             SyncException.wrapWithLocalResource(local) {
                 if (local != null) {
                     logger.log(Level.INFO, "Updating $fileName in local calendar", event)
                     local.eTag = eTag
                     local.scheduleTag = scheduleTag
+
                     local.update(event)
                     syncResult.stats.numUpdates++
                 } else {