diff --git a/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java b/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java
index 0645ed0b97..ccb439d23c 100644
--- a/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java
+++ b/app/src/main/java/eu/faircode/email/BoundaryCallbackMessages.java
@@ -697,7 +697,9 @@ public class BoundaryCallbackMessages extends PagedList.BoundaryCallback<TupleMe
                 String search = query;
 
                 if (!utf8) {
-                    search = search.replace("ß", "ss"); // Eszett
+                    search = search
+                            .replace("ß", "ss") // Eszett
+                            .replace("ij", "ij");
                     search = Normalizer
                             .normalize(search, Normalizer.Form.NFKD)
                             .replaceAll("[^\\p{ASCII}]", "");
diff --git a/app/src/main/java/eu/faircode/email/Core.java b/app/src/main/java/eu/faircode/email/Core.java
index 22b0561cbc..09254cf9f7 100644
--- a/app/src/main/java/eu/faircode/email/Core.java
+++ b/app/src/main/java/eu/faircode/email/Core.java
@@ -3978,7 +3978,9 @@ class Core {
                 if (sb.length() > 0) {
                     String ascii = Normalizer
                             .normalize(sb.toString(), Normalizer.Form.NFKD)
-                            .replaceAll("\\p{InCombiningDiacriticalMarks}+", "");
+                            .replaceAll("\\p{InCombiningDiacriticalMarks}+", "")
+                            .replace("ß", "ss")
+                            .replace("ij", "ij");
                     mbuilder.setContentText(ascii);
                 }