diff --git a/app/src/main/java/me/zhanghai/android/files/compat/MimeTypeMapCompat.kt b/app/src/main/java/me/zhanghai/android/files/compat/MimeTypeMapCompat.kt
index 1702eb78e..226d9947a 100644
--- a/app/src/main/java/me/zhanghai/android/files/compat/MimeTypeMapCompat.kt
+++ b/app/src/main/java/me/zhanghai/android/files/compat/MimeTypeMapCompat.kt
@@ -46,6 +46,7 @@ private val extensionToMimeTypeMap = mapOf(
     "atomsrv" to "application/atomserv+xml",
     "au" to "audio/basic",
     "avi" to "video/avi",
+    "avif" to "image/avif",
     "awb" to "audio/amr-wb",
     "axa" to "audio/annodex",
     "axv" to "video/annodex",
@@ -119,6 +120,7 @@ private val extensionToMimeTypeMap = mapOf(
     "ddeb" to "application/vnd.debian.binary-package",
     "deb" to "application/x-debian-package",
     "deploy" to "application/octet-stream",
+    "der" to "application/x-x509-ca-cert",
     "dfxp" to "application/ttml+xml",
     "dif" to "video/dv",
     "diff" to "text/plain",
diff --git a/mime/MimeTypeMapCompat.kt b/mime/MimeTypeMapCompat.kt
index 120fce3ad..b5209b3a3 100644
--- a/mime/MimeTypeMapCompat.kt
+++ b/mime/MimeTypeMapCompat.kt
@@ -36,6 +36,7 @@ private val extensionToMimeTypeMap = mapOf(
     "atomsrv" to "application/atomserv+xml",
     "au" to "audio/basic",
     "avi" to "video/avi",
+    "avif" to "image/avif",
     "awb" to "audio/amr-wb",
     "axa" to "audio/annodex",
     "axv" to "video/annodex",
@@ -109,6 +110,7 @@ private val extensionToMimeTypeMap = mapOf(
     "ddeb" to "application/vnd.debian.binary-package",
     "deb" to "application/x-debian-package",
     "deploy" to "application/octet-stream",
+    "der" to "application/x-x509-ca-cert",
     "dfxp" to "application/ttml+xml",
     "dif" to "video/dv",
     "diff" to "text/plain",
diff --git a/mime/android.extensions b/mime/android.extensions
index f9dcca277..a9a9b5761 100644
--- a/mime/android.extensions
+++ b/mime/android.extensions
@@ -35,6 +35,7 @@ atomcat application/atomcat+xml
 atomsrv application/atomserv+xml
 au audio/basic
 avi video/avi
+avif image/avif
 awb audio/amr-wb
 axa audio/annodex
 axv video/annodex
@@ -108,6 +109,7 @@ dcr application/x-director
 ddeb application/vnd.debian.binary-package
 deb application/x-debian-package
 deploy application/octet-stream
+der application/x-x509-ca-cert
 dfxp application/ttml+xml
 dif video/dv
 diff text/plain
diff --git a/mime/generate-extensions.sh b/mime/generate-extensions.sh
index f86edc480..21b4e77e1 100755
--- a/mime/generate-extensions.sh
+++ b/mime/generate-extensions.sh
@@ -1,7 +1,7 @@
 #!/bin/bash
 set -e
 
-BRANCH=master
+BRANCH=main
 
 debian_mime_types=$(mktemp)
 android_mime_types=$(mktemp)