diff --git a/src/main/java/io/kamax/mxisd/backend/firebase/GoogleFirebaseProvider.java b/src/main/java/io/kamax/mxisd/backend/firebase/GoogleFirebaseProvider.java
index 17a85c0..4acc953 100644
--- a/src/main/java/io/kamax/mxisd/backend/firebase/GoogleFirebaseProvider.java
+++ b/src/main/java/io/kamax/mxisd/backend/firebase/GoogleFirebaseProvider.java
@@ -49,7 +49,7 @@ public class GoogleFirebaseProvider extends GoogleFirebaseBackend implements ITh
     }
 
     private String getMxid(UserRecord record) {
-        return new MatrixID(record.getUid(), domain).getId();
+        return MatrixID.asAcceptable(record.getUid(), domain).getId();
     }
 
     @Override
diff --git a/src/main/java/io/kamax/mxisd/backend/memory/MemoryIdentityStore.java b/src/main/java/io/kamax/mxisd/backend/memory/MemoryIdentityStore.java
index f4e0203..b78ba04 100644
--- a/src/main/java/io/kamax/mxisd/backend/memory/MemoryIdentityStore.java
+++ b/src/main/java/io/kamax/mxisd/backend/memory/MemoryIdentityStore.java
@@ -148,7 +148,7 @@ public class MemoryIdentityStore implements AuthenticatorProvider, IDirectoryPro
         for (MemoryIdentityConfig id : cfg.getIdentities()) {
             for (MemoryThreePid threepid : id.getThreepids()) {
                 if (req.equals(new ThreePid(threepid.getMedium(), threepid.getAddress()))) {
-                    return Optional.of(new SingleLookupReply(request, new MatrixID(id.getUsername(), mxCfg.getDomain())));
+                    return Optional.of(new SingleLookupReply(request, MatrixID.asAcceptable(id.getUsername(), mxCfg.getDomain())));
                 }
             }
         }
diff --git a/src/main/java/io/kamax/mxisd/backend/rest/RestDirectoryProvider.java b/src/main/java/io/kamax/mxisd/backend/rest/RestDirectoryProvider.java
index 525e22b..a5b9f98 100644
--- a/src/main/java/io/kamax/mxisd/backend/rest/RestDirectoryProvider.java
+++ b/src/main/java/io/kamax/mxisd/backend/rest/RestDirectoryProvider.java
@@ -62,7 +62,7 @@ public class RestDirectoryProvider extends RestProvider implements IDirectoryPro
 
             UserDirectorySearchResult response = parser.parse(httpResponse, UserDirectorySearchResult.class);
             for (UserDirectorySearchResult.Result result : response.getResults()) {
-                result.setUserId(new MatrixID(result.getUserId(), mxCfg.getDomain()).getId());
+                result.setUserId(MatrixID.asAcceptable(result.getUserId(), mxCfg.getDomain()).getId());
             }
 
             return response;
diff --git a/src/main/java/io/kamax/mxisd/backend/rest/RestThreePidProvider.java b/src/main/java/io/kamax/mxisd/backend/rest/RestThreePidProvider.java
index fa0757b..b1e3275 100644
--- a/src/main/java/io/kamax/mxisd/backend/rest/RestThreePidProvider.java
+++ b/src/main/java/io/kamax/mxisd/backend/rest/RestThreePidProvider.java
@@ -60,9 +60,9 @@ public class RestThreePidProvider extends RestProvider implements IThreePidProvi
     // TODO refactor in lookup manager with above FIXME
     private _MatrixID getMxId(UserID id) {
         if (UserIdType.Localpart.is(id.getType())) {
-            return new MatrixID(id.getValue(), mxCfg.getDomain());
+            return MatrixID.asAcceptable(id.getValue(), mxCfg.getDomain());
         } else {
-            return new MatrixID(id.getValue());
+            return MatrixID.asAcceptable(id.getValue());
         }
     }
 
diff --git a/src/main/java/io/kamax/mxisd/backend/sql/SqlThreePidProvider.java b/src/main/java/io/kamax/mxisd/backend/sql/SqlThreePidProvider.java
index fc91485..2a77cbc 100644
--- a/src/main/java/io/kamax/mxisd/backend/sql/SqlThreePidProvider.java
+++ b/src/main/java/io/kamax/mxisd/backend/sql/SqlThreePidProvider.java
@@ -85,11 +85,11 @@ public abstract class SqlThreePidProvider implements IThreePidProvider {
                         log.info("Found match: {}", uid);
                         if (StringUtils.equals("uid", cfg.getIdentity().getType())) {
                             log.info("Resolving as localpart");
-                            return Optional.of(new SingleLookupReply(request, new MatrixID(uid, mxCfg.getDomain())));
+                            return Optional.of(new SingleLookupReply(request, MatrixID.asAcceptable(uid, mxCfg.getDomain())));
                         }
                         if (StringUtils.equals("mxid", cfg.getIdentity().getType())) {
                             log.info("Resolving as MXID");
-                            return Optional.of(new SingleLookupReply(request, new MatrixID(uid)));
+                            return Optional.of(new SingleLookupReply(request, MatrixID.asAcceptable(uid)));
                         }
 
                         log.info("Identity type is unknown, skipping");
diff --git a/src/main/java/io/kamax/mxisd/backend/sql/generic/GenericSqlDirectoryProvider.java b/src/main/java/io/kamax/mxisd/backend/sql/generic/GenericSqlDirectoryProvider.java
index eb24b52..22d6097 100644
--- a/src/main/java/io/kamax/mxisd/backend/sql/generic/GenericSqlDirectoryProvider.java
+++ b/src/main/java/io/kamax/mxisd/backend/sql/generic/GenericSqlDirectoryProvider.java
@@ -86,7 +86,7 @@ public abstract class GenericSqlDirectoryProvider implements IDirectoryProvider
                     while (rSet.next()) {
                         processRow(rSet).ifPresent(e -> {
                             if (StringUtils.equalsIgnoreCase("localpart", query.getType())) {
-                                e.setUserId(new MatrixID(e.getUserId(), mxCfg.getDomain()).getId());
+                                e.setUserId(MatrixID.asAcceptable(e.getUserId(), mxCfg.getDomain()).getId());
                             }
                             result.addResult(e);
                         });
diff --git a/src/main/java/io/kamax/mxisd/controller/identity/v1/InvitationController.java b/src/main/java/io/kamax/mxisd/controller/identity/v1/InvitationController.java
index 62e6d66..f364692 100644
--- a/src/main/java/io/kamax/mxisd/controller/identity/v1/InvitationController.java
+++ b/src/main/java/io/kamax/mxisd/controller/identity/v1/InvitationController.java
@@ -73,7 +73,7 @@ class InvitationController {
         for (String key : request.getParameterMap().keySet()) {
             parameters.put(key, request.getParameter(key));
         }
-        IThreePidInvite invite = new ThreePidInvite(new MatrixID(sender), medium, address, roomId, parameters);
+        IThreePidInvite invite = new ThreePidInvite(MatrixID.asAcceptable(sender), medium, address, roomId, parameters);
         IThreePidInviteReply reply = mgr.storeInvite(invite);
 
         return gson.toJson(new ThreePidInviteReplyIO(reply, keyMgr.getPublicKeyBase64(keyMgr.getCurrentIndex()), srvCfg.getPublicUrl()));
diff --git a/src/main/java/io/kamax/mxisd/invitation/InvitationManager.java b/src/main/java/io/kamax/mxisd/invitation/InvitationManager.java
index c185452..198d122 100644
--- a/src/main/java/io/kamax/mxisd/invitation/InvitationManager.java
+++ b/src/main/java/io/kamax/mxisd/invitation/InvitationManager.java
@@ -108,7 +108,7 @@ public class InvitationManager {
         ioList.forEach(io -> {
             log.info("Processing invite {}", gson.toJson(io));
             ThreePidInvite invite = new ThreePidInvite(
-                    new MatrixID(io.getSender()),
+                    MatrixID.asAcceptable(io.getSender()),
                     io.getMedium(),
                     io.getAddress(),
                     io.getRoomId(),
diff --git a/src/main/java/io/kamax/mxisd/lookup/SingleLookupReply.java b/src/main/java/io/kamax/mxisd/lookup/SingleLookupReply.java
index ee5c4af..0c13f13 100644
--- a/src/main/java/io/kamax/mxisd/lookup/SingleLookupReply.java
+++ b/src/main/java/io/kamax/mxisd/lookup/SingleLookupReply.java
@@ -48,7 +48,7 @@ public class SingleLookupReply {
 
         try {
             SingeLookupReplyJson json = gson.fromJson(body, SingeLookupReplyJson.class);
-            reply.mxid = new MatrixID(json.getMxid());
+            reply.mxid = MatrixID.asAcceptable(json.getMxid());
             reply.notAfter = Instant.ofEpochMilli(json.getNot_after());
             reply.notBefore = Instant.ofEpochMilli(json.getNot_before());
             reply.timestamp = Instant.ofEpochMilli(json.getTs());
@@ -64,7 +64,7 @@ public class SingleLookupReply {
     }
 
     public SingleLookupReply(SingleLookupRequest request, String mxid) {
-        this(request, new MatrixID(mxid));
+        this(request, MatrixID.asAcceptable(mxid));
     }
 
     public SingleLookupReply(SingleLookupRequest request, _MatrixID mxid) {
diff --git a/src/main/java/io/kamax/mxisd/session/SessionMananger.java b/src/main/java/io/kamax/mxisd/session/SessionMananger.java
index f14735e..487e6b3 100644
--- a/src/main/java/io/kamax/mxisd/session/SessionMananger.java
+++ b/src/main/java/io/kamax/mxisd/session/SessionMananger.java
@@ -218,7 +218,7 @@ public class SessionMananger {
     }
 
     public void bind(String sid, String secret, String mxidRaw) {
-        _MatrixID mxid = new MatrixID(mxidRaw);
+        _MatrixID mxid = MatrixID.asAcceptable(mxidRaw);
         ThreePidSession session = getSessionIfValidated(sid, secret);
 
         if (!session.isRemote()) {
diff --git a/src/test/java/io/kamax/mxisd/backend/rest/RestDirectoryProviderTest.java b/src/test/java/io/kamax/mxisd/backend/rest/RestDirectoryProviderTest.java
index 00aeab6..f861b99 100644
--- a/src/test/java/io/kamax/mxisd/backend/rest/RestDirectoryProviderTest.java
+++ b/src/test/java/io/kamax/mxisd/backend/rest/RestDirectoryProviderTest.java
@@ -93,7 +93,7 @@ public class RestDirectoryProviderTest {
         assertNotNull(entry);
         assertTrue(StringUtils.equals(byNameAvatar, entry.getAvatarUrl()));
         assertTrue(StringUtils.equals(byNameDisplay, entry.getDisplayName()));
-        assertTrue(StringUtils.equals(new MatrixID(byNameId, domain).getId(), entry.getUserId()));
+        assertTrue(StringUtils.equals(MatrixID.asAcceptable(byNameId, domain).getId(), entry.getUserId()));
 
         verify(postRequestedFor(urlMatching(endpoint))
                 .withHeader("Content-Type", containing("application/json"))
@@ -136,7 +136,7 @@ public class RestDirectoryProviderTest {
         assertNotNull(entry);
         assertTrue(StringUtils.equals(byThreepidAvatar, entry.getAvatarUrl()));
         assertTrue(StringUtils.equals(byThreepidDisplay, entry.getDisplayName()));
-        assertTrue(StringUtils.equals(new MatrixID(byThreepidId, domain).getId(), entry.getUserId()));
+        assertTrue(StringUtils.equals(MatrixID.asAcceptable(byThreepidId, domain).getId(), entry.getUserId()));
 
         verify(postRequestedFor(urlMatching(endpoint))
                 .withHeader("Content-Type", containing("application/json"))