diff --git a/services/collaboration/pkg/helpers/discovery.go b/services/collaboration/pkg/helpers/discovery.go
index 2db3987739..a2c1834a49 100644
--- a/services/collaboration/pkg/helpers/discovery.go
+++ b/services/collaboration/pkg/helpers/discovery.go
@@ -59,14 +59,17 @@ func (a *AppURLs) GetMimeTypes() []string {
 }
 
 // GetAppURLFor gets the appURL from the list of appURLs based on the
-// action and file extension provided. If there is no match, an empty
-// string will be returned.
+// action and file extension provided. The extension is matched without
+// case, so a "report.DOCX" opens in the same app as a "report.docx".
+// If there is no match, an empty string will be returned.
 func (a *AppURLs) GetAppURLFor(action, fileExt string) string {
 	currentURLs := a.urls.Load()
 	if currentURLs == nil {
 		return ""
 	}
 
+	fileExt = strings.ToLower(fileExt)
+
 	if actionURL, ok := (*currentURLs)[action]; ok {
 		if actionExtensionURL, ok := actionURL[fileExt]; ok {
 			return actionExtensionURL
@@ -162,7 +165,8 @@ func parseWopiDiscovery(body io.Reader) (map[string]map[string]string, error) {
 						if _, ok := appURLs[access]; !ok {
 							appURLs[access] = make(map[string]string)
 						}
-						appURLs[access]["."+ext] = u.String()
+						// the extensions are stored in lower case, GetAppURLFor looks them up that way
+						appURLs[access]["."+strings.ToLower(ext)] = u.String()
 					}
 				}
 			}
diff --git a/services/collaboration/pkg/helpers/discovery_test.go b/services/collaboration/pkg/helpers/discovery_test.go
index 6891323f35..8416e032e1 100644
--- a/services/collaboration/pkg/helpers/discovery_test.go
+++ b/services/collaboration/pkg/helpers/discovery_test.go
@@ -49,6 +49,18 @@ var _ = Describe("AppURLs", func() {
 			Expect(appURLs.GetAppURLFor("edit", ".docx")).To(Equal("https://example.com/edit/docx"))
 		})
 
+		It("should find the app URL whatever case the extension has", func() {
+			testURLs := map[string]map[string]string{
+				"view": {".docx": "https://example.com/view/docx"},
+				"edit": {".docx": "https://example.com/edit/docx"},
+			}
+
+			appURLs.Store(testURLs)
+
+			Expect(appURLs.GetAppURLFor("view", ".DOCX")).To(Equal("https://example.com/view/docx"))
+			Expect(appURLs.GetAppURLFor("edit", ".DocX")).To(Equal("https://example.com/edit/docx"))
+		})
+
 		It("should return empty string for non-existent action", func() {
 			testURLs := map[string]map[string]string{
 				"view": {".pdf": "https://example.com/view/pdf"},
@@ -285,6 +297,7 @@ var _ = Describe("Discovery", func() {
     <app name="Word" favIconUrl="https://cloud.opencloud.test/web-apps/apps/documenteditor/main/resources/img/favicon.ico">
       <action name="view" ext="pdf" urlsrc="https://cloud.opencloud.test/hosting/wopi/word/view?&amp;&lt;rs=DC_LLCC&amp;&gt;&lt;dchat=DISABLE_CHAT&amp;&gt;&lt;embed=EMBEDDED&amp;&gt;&lt;fs=FULLSCREEN&amp;&gt;&lt;hid=HOST_SESSION_ID&amp;&gt;&lt;rec=RECORDING&amp;&gt;&lt;sc=SESSION_CONTEXT&amp;&gt;&lt;thm=THEME_ID&amp;&gt;&lt;ui=UI_LLCC&amp;&gt;&lt;wopisrc=WOPI_SOURCE&amp;&gt;&amp;"/>
       <action name="embedview" ext="pdf" urlsrc="https://cloud.opencloud.test/hosting/wopi/word/view?embed=1&amp;&lt;rs=DC_LLCC&amp;&gt;&lt;dchat=DISABLE_CHAT&amp;&gt;&lt;embed=EMBEDDED&amp;&gt;&lt;fs=FULLSCREEN&amp;&gt;&lt;hid=HOST_SESSION_ID&amp;&gt;&lt;rec=RECORDING&amp;&gt;&lt;sc=SESSION_CONTEXT&amp;&gt;&lt;thm=THEME_ID&amp;&gt;&lt;ui=UI_LLCC&amp;&gt;&lt;wopisrc=WOPI_SOURCE&amp;&gt;&amp;"/>
+      <action name="view" ext="ODT" urlsrc="https://cloud.opencloud.test/hosting/wopi/word/view"/>
       <action name="view" ext="djvu" urlsrc="https://cloud.opencloud.test/hosting/wopi/word/view?&amp;&lt;rs=DC_LLCC&amp;&gt;&lt;dchat=DISABLE_CHAT&amp;&gt;&lt;embed=EMBEDDED&amp;&gt;&lt;fs=FULLSCREEN&amp;&gt;&lt;hid=HOST_SESSION_ID&amp;&gt;&lt;rec=RECORDING&amp;&gt;&lt;sc=SESSION_CONTEXT&amp;&gt;&lt;thm=THEME_ID&amp;&gt;&lt;ui=UI_LLCC&amp;&gt;&lt;wopisrc=WOPI_SOURCE&amp;&gt;&amp;"/>
       <action name="embedview" ext="djvu" urlsrc="https://cloud.opencloud.test/hosting/wopi/word/view?embed=1&amp;&lt;rs=DC_LLCC&amp;&gt;&lt;dchat=DISABLE_CHAT&amp;&gt;&lt;embed=EMBEDDED&amp;&gt;&lt;fs=FULLSCREEN&amp;&gt;&lt;hid=HOST_SESSION_ID&amp;&gt;&lt;rec=RECORDING&amp;&gt;&lt;sc=SESSION_CONTEXT&amp;&gt;&lt;thm=THEME_ID&amp;&gt;&lt;ui=UI_LLCC&amp;&gt;&lt;wopisrc=WOPI_SOURCE&amp;&gt;&amp;"/>
       <action name="view" ext="docx" urlsrc="https://cloud.opencloud.test/hosting/wopi/word/view?&amp;&lt;rs=DC_LLCC&amp;&gt;&lt;dchat=DISABLE_CHAT&amp;&gt;&lt;embed=EMBEDDED&amp;&gt;&lt;fs=FULLSCREEN&amp;&gt;&lt;hid=HOST_SESSION_ID&amp;&gt;&lt;rec=RECORDING&amp;&gt;&lt;sc=SESSION_CONTEXT&amp;&gt;&lt;thm=THEME_ID&amp;&gt;&lt;ui=UI_LLCC&amp;&gt;&lt;wopisrc=WOPI_SOURCE&amp;&gt;&amp;"/>
@@ -339,6 +352,7 @@ var _ = Describe("Discovery", func() {
 				"view": map[string]string{
 					".pdf":  "https://cloud.opencloud.test/hosting/wopi/word/view",
 					".djvu": "https://cloud.opencloud.test/hosting/wopi/word/view",
+					".odt":  "https://cloud.opencloud.test/hosting/wopi/word/view",
 					".docx": "https://cloud.opencloud.test/hosting/wopi/word/view",
 					".xls":  "https://cloud.opencloud.test/hosting/wopi/cell/view",
 					".xlsb": "https://cloud.opencloud.test/hosting/wopi/cell/view",
diff --git a/services/collaboration/pkg/service/grpc/v0/service.go b/services/collaboration/pkg/service/grpc/v0/service.go
index 4e9a6db73a..b68be18d9d 100644
--- a/services/collaboration/pkg/service/grpc/v0/service.go
+++ b/services/collaboration/pkg/service/grpc/v0/service.go
@@ -108,8 +108,8 @@ func (s *Service) OpenInApp(
 	// get the appURL we need to use
 	appURL := s.getAppUrl(fileExt, req.GetViewMode())
 	if appURL == "" {
-		logger.Error().Msg("OpenInApp: neither edit nor view app URL found")
-		return nil, errors.New("neither edit nor view app URL found")
+		logger.Error().Str("FileExtension", fileExt).Msg("OpenInApp: neither edit nor view app URL found")
+		return nil, errors.New("neither edit nor view app URL found for " + fileExt)
 	}
 
 	// append the parameters we need