diff --git a/CHANGES.md b/CHANGES.md
index 0c55b621c38..24822766ec8 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -18,6 +18,7 @@ Bugfix 🐛:
  - Fix wording issue (#3242)
  - Fix missing sender information after edits (#3184)
  - Fix read marker not updating automatically (#3267)
+ - Remove redundant mimetype (vector-im/element-web#2547)
 
 Translations 🗣:
  -
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageAudioContent.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageAudioContent.kt
index fcf3d73cbea..b4ba5c0a66e 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageAudioContent.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageAudioContent.kt
@@ -54,5 +54,5 @@ data class MessageAudioContent(
 ) : MessageWithAttachmentContent {
 
     override val mimeType: String?
-        get() = encryptedFileInfo?.mimetype ?: audioInfo?.mimeType
+        get() = audioInfo?.mimeType
 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageFileContent.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageFileContent.kt
index d93f115322a..96877b4d9f1 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageFileContent.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageFileContent.kt
@@ -60,8 +60,7 @@ data class MessageFileContent(
 ) : MessageWithAttachmentContent {
 
     override val mimeType: String?
-        get() = encryptedFileInfo?.mimetype
-                ?: info?.mimeType
+        get() = info?.mimeType
                 ?: MimeTypeMap.getFileExtensionFromUrl(filename ?: body)?.let { extension ->
                     MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension)
                 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageImageContent.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageImageContent.kt
index 73e27b64e31..73fd1eab565 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageImageContent.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageImageContent.kt
@@ -20,7 +20,6 @@ import com.squareup.moshi.Json
 import com.squareup.moshi.JsonClass
 import org.matrix.android.sdk.api.session.events.model.Content
 import org.matrix.android.sdk.api.session.room.model.relation.RelationDefaultContent
-import org.matrix.android.sdk.api.util.MimeTypes
 import org.matrix.android.sdk.internal.crypto.model.rest.EncryptedFileInfo
 
 @JsonClass(generateAdapter = true)
@@ -55,5 +54,5 @@ data class MessageImageContent(
         @Json(name = "file") override val encryptedFileInfo: EncryptedFileInfo? = null
 ) : MessageImageInfoContent {
     override val mimeType: String?
-        get() = encryptedFileInfo?.mimetype ?: info?.mimeType ?: MimeTypes.Images
+        get() = info?.mimeType
 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageStickerContent.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageStickerContent.kt
index 280316d4b52..8e1d4d3d758 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageStickerContent.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageStickerContent.kt
@@ -55,5 +55,5 @@ data class MessageStickerContent(
         @Json(name = "file") override val encryptedFileInfo: EncryptedFileInfo? = null
 ) : MessageImageInfoContent {
     override val mimeType: String?
-        get() = encryptedFileInfo?.mimetype ?: info?.mimeType
+        get() = info?.mimeType
 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageVideoContent.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageVideoContent.kt
index b7581c9fbf8..3f5d2dab2e7 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageVideoContent.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/api/session/room/model/message/MessageVideoContent.kt
@@ -53,5 +53,5 @@ data class MessageVideoContent(
         @Json(name = "file") override val encryptedFileInfo: EncryptedFileInfo? = null
 ) : MessageWithAttachmentContent {
     override val mimeType: String?
-        get() = encryptedFileInfo?.mimetype ?: videoInfo?.mimeType
+        get() = videoInfo?.mimeType
 }
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/attachments/MXEncryptedAttachments.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/attachments/MXEncryptedAttachments.kt
index 5a9852b6db7..70730326da1 100755
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/attachments/MXEncryptedAttachments.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/attachments/MXEncryptedAttachments.kt
@@ -39,7 +39,9 @@ internal object MXEncryptedAttachments {
     private const val SECRET_KEY_SPEC_ALGORITHM = "AES"
     private const val MESSAGE_DIGEST_ALGORITHM = "SHA-256"
 
-    fun encrypt(clearStream: InputStream, mimetype: String?, outputFile: File, progress: ((current: Int, total: Int) -> Unit)): EncryptedFileInfo {
+    fun encrypt(clearStream: InputStream,
+                outputFile: File,
+                progress: ((current: Int, total: Int) -> Unit)): EncryptedFileInfo {
         val t0 = System.currentTimeMillis()
         val secureRandom = SecureRandom()
         val initVectorBytes = ByteArray(16) { 0.toByte() }
@@ -86,7 +88,6 @@ internal object MXEncryptedAttachments {
 
         return EncryptedFileInfo(
                 url = null,
-                mimetype = mimetype,
                 key = EncryptedFileKey(
                         alg = "A256CTR",
                         ext = true,
@@ -155,10 +156,9 @@ internal object MXEncryptedAttachments {
      * Encrypt an attachment stream.
      * DO NOT USE for big files, it will load all in memory
      * @param attachmentStream the attachment stream. Will be closed after this method call.
-     * @param mimetype the mime type
      * @return the encryption file info
      */
-    fun encryptAttachment(attachmentStream: InputStream, mimetype: String?): EncryptionResult {
+    fun encryptAttachment(attachmentStream: InputStream): EncryptionResult {
         val t0 = System.currentTimeMillis()
         val secureRandom = SecureRandom()
 
@@ -207,7 +207,6 @@ internal object MXEncryptedAttachments {
         return EncryptionResult(
                 encryptedFileInfo = EncryptedFileInfo(
                         url = null,
-                        mimetype = mimetype,
                         key = EncryptedFileKey(
                                 alg = "A256CTR",
                                 ext = true,
@@ -232,7 +231,9 @@ internal object MXEncryptedAttachments {
      * @param outputStream     the outputStream where the decrypted attachment will be write.
      * @return true in case of success, false in case of error
      */
-    fun decryptAttachment(attachmentStream: InputStream?, elementToDecrypt: ElementToDecrypt?, outputStream: OutputStream): Boolean {
+    fun decryptAttachment(attachmentStream: InputStream?,
+                          elementToDecrypt: ElementToDecrypt?,
+                          outputStream: OutputStream): Boolean {
         // sanity checks
         if (null == attachmentStream || elementToDecrypt == null) {
             Timber.e("## decryptAttachment() : null stream")
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/model/rest/EncryptedFileInfo.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/model/rest/EncryptedFileInfo.kt
index 0ed6c0dac93..4fc3adb42cc 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/model/rest/EncryptedFileInfo.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/crypto/model/rest/EncryptedFileInfo.kt
@@ -29,12 +29,6 @@ data class EncryptedFileInfo(
         @Json(name = "url")
         val url: String? = null,
 
-        /**
-         * Not documented
-         */
-        @Json(name = "mimetype")
-        val mimetype: String? = null,
-
         /**
          * Required. A JSON Web Key object.
          */
diff --git a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/content/UploadContentWorker.kt b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/content/UploadContentWorker.kt
index 3b727690bfd..492bed7a36d 100644
--- a/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/content/UploadContentWorker.kt
+++ b/matrix-sdk-android/src/main/java/org/matrix/android/sdk/internal/session/content/UploadContentWorker.kt
@@ -186,7 +186,7 @@ internal class UploadContentWorker(val context: Context, params: WorkerParameter
                             .also { filesToDelete.add(it) }
 
                     uploadedFileEncryptedFileInfo =
-                            MXEncryptedAttachments.encrypt(fileToUpload.inputStream(), attachment.getSafeMimeType(), encryptedFile) { read, total ->
+                            MXEncryptedAttachments.encrypt(fileToUpload.inputStream(), encryptedFile) { read, total ->
                                 notifyTracker(params) {
                                     contentUploadStateTracker.setEncrypting(it, read.toLong(), total.toLong())
                                 }
@@ -259,7 +259,7 @@ internal class UploadContentWorker(val context: Context, params: WorkerParameter
                         if (params.isEncrypted) {
                             Timber.v("Encrypt thumbnail")
                             notifyTracker(params) { contentUploadStateTracker.setEncryptingThumbnail(it) }
-                            val encryptionResult = MXEncryptedAttachments.encryptAttachment(thumbnailData.bytes.inputStream(), thumbnailData.mimeType)
+                            val encryptionResult = MXEncryptedAttachments.encryptAttachment(thumbnailData.bytes.inputStream())
                             val contentUploadResponse = fileUploader.uploadByteArray(encryptionResult.encryptedByteArray,
                                     "thumb_${params.attachment.name}",
                                     MimeTypes.OctetStream,