diff --git a/src/Channel.sol b/src/Channel.sol
index 8de59d6..48c678b 100644
--- a/src/Channel.sol
+++ b/src/Channel.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "./UserConfig.sol";
diff --git a/src/Common.sol b/src/Common.sol
index f99c90a..d1ca019 100644
--- a/src/Common.sol
+++ b/src/Common.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 /// @dev The block of control information and data for comminicate
diff --git a/src/ORMP.sol b/src/ORMP.sol
index 3041235..7e84205 100644
--- a/src/ORMP.sol
+++ b/src/ORMP.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "./Channel.sol";
diff --git a/src/UserConfig.sol b/src/UserConfig.sol
index 0e96e9a..f2cbe9f 100644
--- a/src/UserConfig.sol
+++ b/src/UserConfig.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 /// @dev User application custom configuration.
diff --git a/src/Verifier.sol b/src/Verifier.sol
index 2a5cb02..6c229bf 100644
--- a/src/Verifier.sol
+++ b/src/Verifier.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "./interfaces/IVerifier.sol";
diff --git a/src/eco/Oracle.sol b/src/eco/Oracle.sol
index 92c6bc9..29d4d47 100644
--- a/src/eco/Oracle.sol
+++ b/src/eco/Oracle.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "../Verifier.sol";
diff --git a/src/eco/Relayer.sol b/src/eco/Relayer.sol
index b72d575..c12a3ef 100644
--- a/src/eco/Relayer.sol
+++ b/src/eco/Relayer.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "../interfaces/IORMP.sol";
diff --git a/src/interfaces/IORMP.sol b/src/interfaces/IORMP.sol
index f2b12de..2d310e3 100644
--- a/src/interfaces/IORMP.sol
+++ b/src/interfaces/IORMP.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "../Common.sol";
diff --git a/src/interfaces/IOracle.sol b/src/interfaces/IOracle.sol
index e22658f..063dd4c 100644
--- a/src/interfaces/IOracle.sol
+++ b/src/interfaces/IOracle.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "./IVerifier.sol";
diff --git a/src/interfaces/IRelayer.sol b/src/interfaces/IRelayer.sol
index 8df0d86..ff35c95 100644
--- a/src/interfaces/IRelayer.sol
+++ b/src/interfaces/IRelayer.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 interface IRelayer {
diff --git a/src/interfaces/IVerifier.sol b/src/interfaces/IVerifier.sol
index f5e6d8d..2e56b31 100644
--- a/src/interfaces/IVerifier.sol
+++ b/src/interfaces/IVerifier.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "../Common.sol";
diff --git a/src/security/ReentrancyGuard.sol b/src/security/ReentrancyGuard.sol
index ebb11f8..790fb8e 100644
--- a/src/security/ReentrancyGuard.sol
+++ b/src/security/ReentrancyGuard.sol
@@ -1,5 +1,4 @@
 // SPDX-License-Identifier: MIT
-
 pragma solidity 0.8.17;
 
 abstract contract ReentrancyGuard {
diff --git a/src/user/AppBase.sol b/src/user/AppBase.sol
index 6a0c4a2..989b842 100644
--- a/src/user/AppBase.sol
+++ b/src/user/AppBase.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
 import "../interfaces/IORMP.sol";
diff --git a/src/user/Application.sol b/src/user/Application.sol
index 7ed6718..ab2ba36 100644
--- a/src/user/Application.sol
+++ b/src/user/Application.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity ^0.8.17;
 
 import "./AppBase.sol";
diff --git a/test/Channel.t.sol b/test/Channel.t.sol
index 0006def..104c9e1 100644
--- a/test/Channel.t.sol
+++ b/test/Channel.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/Common.t.sol b/test/Common.t.sol
index f4dc31f..ccef8f6 100644
--- a/test/Common.t.sol
+++ b/test/Common.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/ORMP.m.sol b/test/ORMP.m.sol
index c0be4fe..e5c2740 100644
--- a/test/ORMP.m.sol
+++ b/test/ORMP.m.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "../src/ORMP.sol";
diff --git a/test/ORMP.t.sol b/test/ORMP.t.sol
index 8d1d2e0..46a7654 100644
--- a/test/ORMP.t.sol
+++ b/test/ORMP.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/UserConfig.t.sol b/test/UserConfig.t.sol
index 01b5df8..017ccd4 100644
--- a/test/UserConfig.t.sol
+++ b/test/UserConfig.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/bench/ORMP.b.sol b/test/bench/ORMP.b.sol
index 7e69457..8f49c7a 100644
--- a/test/bench/ORMP.b.sol
+++ b/test/bench/ORMP.b.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/eco/Oracle.t.sol b/test/eco/Oracle.t.sol
index 3174e02..7745cfb 100644
--- a/test/eco/Oracle.t.sol
+++ b/test/eco/Oracle.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/eco/Relayer.t.sol b/test/eco/Relayer.t.sol
index 6b10006..62de712 100644
--- a/test/eco/Relayer.t.sol
+++ b/test/eco/Relayer.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/security/ExcessivelySafeCall.t.sol b/test/security/ExcessivelySafeCall.t.sol
index d4fe93d..3152212 100644
--- a/test/security/ExcessivelySafeCall.t.sol
+++ b/test/security/ExcessivelySafeCall.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity >=0.8.17;
 
 import "forge-std/Test.sol";
diff --git a/test/user/Application.t.sol b/test/user/Application.t.sol
index 68784d5..1c8d9aa 100644
--- a/test/user/Application.t.sol
+++ b/test/user/Application.t.sol
@@ -1,20 +1,4 @@
-// This file is part of Darwinia.
-// Copyright (C) 2018-2023 Darwinia Network
-// SPDX-License-Identifier: GPL-3.0
-//
-// Darwinia is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// Darwinia is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-// GNU General Public License for more details.
-//
-// You should have received a copy of the GNU General Public License
-// along with Darwinia. If not, see <https://www.gnu.org/licenses/>.
-
+// SPDX-License-Identifier: MIT
 pragma solidity 0.8.17;
 
 import "forge-std/Test.sol";