diff --git a/custom/conf/app.example.ini b/custom/conf/app.example.ini
index a15b9be54fc04..2912a0584e208 100644
--- a/custom/conf/app.example.ini
+++ b/custom/conf/app.example.ini
@@ -745,7 +745,7 @@ ENABLED = true
 ; Path for attachments. Defaults to `data/attachments`
 PATH = data/attachments
 ; One or more allowed types, e.g. "image/jpeg|image/png". Use "*/*" for all types.
-ALLOWED_TYPES = image/jpeg|image/png|application/zip|application/gzip
+ALLOWED_TYPES = image/jpeg|image/png|application/zip|application/x-zip-compressed|application/gzip
 ; Max size of each file. Defaults to 4MB
 MAX_SIZE = 4
 ; Max number of files per upload. Defaults to 5
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index f98addb3cdd3f..bb1e53e94953e 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -839,7 +839,7 @@ func NewContext() {
 	if !filepath.IsAbs(AttachmentPath) {
 		AttachmentPath = path.Join(AppWorkPath, AttachmentPath)
 	}
-	AttachmentAllowedTypes = strings.Replace(sec.Key("ALLOWED_TYPES").MustString("image/jpeg,image/png,application/zip,application/gzip"), "|", ",", -1)
+	AttachmentAllowedTypes = strings.Replace(sec.Key("ALLOWED_TYPES").MustString("image/jpeg,image/png,application/zip,application/x-zip-compressed,application/gzip"), "|", ",", -1)
 	AttachmentMaxSize = sec.Key("MAX_SIZE").MustInt64(4)
 	AttachmentMaxFiles = sec.Key("MAX_FILES").MustInt(5)
 	AttachmentEnabled = sec.Key("ENABLED").MustBool(true)