diff --git a/state/user.go b/state/user.go
index 812a1fbf..bb7caa34 100644
--- a/state/user.go
+++ b/state/user.go
@@ -153,6 +153,7 @@ func NewStubUser(screenName DisplayScreenName) (User, error) {
 		IdentScreenName:   NewIdentScreenName(string(screenName)),
 		DisplayScreenName: screenName,
 		AuthKey:           uid.String(),
+		IsICQ:             screenName.IsUIN(),
 	}
 	err = u.HashPassword("welcome1")
 	return u, err
diff --git a/state/user_store.go b/state/user_store.go
index d9e31837..ab2c8ceb 100644
--- a/state/user_store.go
+++ b/state/user_store.go
@@ -70,10 +70,12 @@ func (f SQLiteUserStore) runMigrations() error {
 	return nil
 }
 
-// AllUsers returns all stored users. It only populates the User.IdentScreenName and
-// User.DisplayScreenName fields in the return slice.
+// AllUsers returns all stored users. It only populates the following fields:
+// - IdentScreenName
+// - DisplayScreenName
+// - IsICQ
 func (f SQLiteUserStore) AllUsers() ([]User, error) {
-	q := `SELECT identScreenName, displayScreenName FROM users`
+	q := `SELECT identScreenName, displayScreenName, isICQ FROM users`
 	rows, err := f.db.Query(q)
 	if err != nil {
 		return nil, err
@@ -83,12 +85,14 @@ func (f SQLiteUserStore) AllUsers() ([]User, error) {
 	var users []User
 	for rows.Next() {
 		var identSN, displaySN string
-		if err := rows.Scan(&identSN, &displaySN); err != nil {
+		var isICQ bool
+		if err := rows.Scan(&identSN, &displaySN, &isICQ); err != nil {
 			return nil, err
 		}
 		users = append(users, User{
 			IdentScreenName:   NewIdentScreenName(identSN),
 			DisplayScreenName: DisplayScreenName(displaySN),
+			IsICQ:             isICQ,
 		})
 	}
 
@@ -372,6 +376,9 @@ func getUsers(filterFN filterFN, tx queryer) ([]User, error) {
 // InsertUser inserts a user to the store. Return ErrDupUser if a user with the
 // same screen name already exists.
 func (f SQLiteUserStore) InsertUser(u User) error {
+	if u.DisplayScreenName.IsUIN() && !u.IsICQ {
+		return errors.New("inserting user with UIN and isICQ=false")
+	}
 	q := `
 		INSERT INTO users (identScreenName, displayScreenName, authKey, weakMD5Pass, strongMD5Pass, isICQ)
 		VALUES (?, ?, ?, ?, ?, ?)
diff --git a/state/user_store_test.go b/state/user_store_test.go
index 59729621..fbe4bc8d 100644
--- a/state/user_store_test.go
+++ b/state/user_store_test.go
@@ -445,9 +445,7 @@ func TestSQLiteUserStore_Users(t *testing.T) {
 	}()
 
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	want := []User{
 		{
@@ -462,6 +460,11 @@ func TestSQLiteUserStore_Users(t *testing.T) {
 			IdentScreenName:   NewIdentScreenName("userC"),
 			DisplayScreenName: "userC",
 		},
+		{
+			IdentScreenName:   NewIdentScreenName("100003"),
+			DisplayScreenName: "100003",
+			IsICQ:             true,
+		},
 	}
 
 	for _, u := range want {
@@ -475,6 +478,23 @@ func TestSQLiteUserStore_Users(t *testing.T) {
 	assert.Equal(t, want, have)
 }
 
+func TestSQLiteUserStore_InsertUser_UINButNotIsICQ(t *testing.T) {
+	defer func() {
+		assert.NoError(t, os.Remove(testFile))
+	}()
+
+	f, err := NewSQLiteUserStore(testFile)
+	assert.NoError(t, err)
+
+	user := User{
+		IdentScreenName:   NewIdentScreenName("100003"),
+		DisplayScreenName: "100003",
+	}
+
+	err = f.InsertUser(user)
+	assert.ErrorContains(t, err, "inserting user with UIN and isICQ=false")
+}
+
 func TestSQLiteUserStore_DeleteUser_DeleteExistentUser(t *testing.T) {
 	defer func() {
 		assert.NoError(t, os.Remove(testFile))
@@ -840,9 +860,7 @@ func TestSQLiteUserStore_SetWorkInfo(t *testing.T) {
 	}()
 
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	screenName := NewIdentScreenName("testuser")
 	user := User{
@@ -930,9 +948,7 @@ func TestSQLiteUserStore_SetMoreInfo(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create a test user
 	screenName := NewIdentScreenName("testuser")
@@ -1009,9 +1025,7 @@ func TestSQLiteUserStore_SetUserNotes(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create a test user
 	screenName := NewIdentScreenName("testuser")
@@ -1067,9 +1081,7 @@ func TestSQLiteUserStore_SetInterests(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create a test user
 	screenName := NewIdentScreenName("testuser")
@@ -1146,9 +1158,7 @@ func TestSQLiteUserStore_SetAffiliations(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create a test user
 	screenName := NewIdentScreenName("testuser")
@@ -1237,9 +1247,7 @@ func TestSQLiteUserStore_SetBasicInfo(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create a test user
 	screenName := NewIdentScreenName("testuser")
@@ -1334,9 +1342,7 @@ func TestSQLiteUserStore_FindByInterests(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create and set up test users with different interests
 	user1 := User{
@@ -1444,9 +1450,7 @@ func TestSQLiteUserStore_FindByDetails(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create and set up test users with different details using SetBasicInfo
 	user1 := User{
@@ -1556,9 +1560,7 @@ func TestSQLiteUserStore_FindByEmail(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create and set up test users with different email addresses using SetBasicInfo
 	user1 := User{
@@ -1626,9 +1628,7 @@ func TestSQLiteUserStore_FindByUIN(t *testing.T) {
 
 	// Initialize the SQLiteUserStore with a test database file
 	f, err := NewSQLiteUserStore(testFile)
-	if err != nil {
-		assert.NoError(t, err)
-	}
+	assert.NoError(t, err)
 
 	// Create and set up test users where UIN is the same as IdentScreenName
 	user1 := User{