diff --git a/.github/workflows/spec_test_on_nuttx.yml b/.github/workflows/spec_test_on_nuttx.yml
index a65a03bf9c..dc9d469b11 100644
--- a/.github/workflows/spec_test_on_nuttx.yml
+++ b/.github/workflows/spec_test_on_nuttx.yml
@@ -37,6 +37,19 @@ jobs:
     permissions:
       contents: read
       actions: write
+    uses: jlumbroso/free-disk-space@v1.3.1
+    with:
+      # Deletes Android, Haskell, and .NET runtimes from the runner, freeing
+      # about 15 GB.  
+      android: true
+      dotnet: true
+      haskell: true
+      # Keeps the tool cache, some large packages, docker images, and swap.
+      # Some of these could also be removed if more space is needed.
+      tool-cache: false
+      large-packages: false
+      docker-images: false
+      swap-storage: false
     uses: ./.github/workflows/build_llvm_libraries.yml
     with:
       os: "ubuntu-22.04"
diff --git a/build-scripts/build_llvm.py b/build-scripts/build_llvm.py
index 3d241355b4..28c815894e 100755
--- a/build-scripts/build_llvm.py
+++ b/build-scripts/build_llvm.py
@@ -294,7 +294,7 @@ def main():
         "arc": {
             "repo": "https://github.com/llvm/llvm-project.git",
             "repo_ssh": "git@github.com:llvm/llvm-project.git",
-            "branch": "release/18.x",
+            "branch": "release/21.x",
         },
         "xtensa": {
             "repo": "https://github.com/espressif/llvm-project.git",
@@ -304,7 +304,7 @@ def main():
         "default": {
             "repo": "https://github.com/llvm/llvm-project.git",
             "repo_ssh": "git@github.com:llvm/llvm-project.git",
-            "branch": "release/18.x",
+            "branch": "release/21.x",
         },
     }
 
diff --git a/core/iwasm/compilation/aot_llvm.c b/core/iwasm/compilation/aot_llvm.c
index ab351e6d44..1259930b49 100644
--- a/core/iwasm/compilation/aot_llvm.c
+++ b/core/iwasm/compilation/aot_llvm.c
@@ -2656,6 +2656,25 @@ aot_create_comp_context(const AOTCompData *comp_data, aot_comp_option_t option)
     comp_ctx->comp_data = comp_data;
 
     /* Create LLVM context, module and builder */
+#if LLVM_VERSION_MAJOR >= 21
+    /* Construct an LLVMContext directly, note:
+         different from non LAZY JIT mode, no need to dispose this context, if
+         will be disposed when the thread safe context is disposed */
+    comp_ctx->context = LLVMContextCreate();
+    if (!comp_ctx->context) {
+        aot_set_last_error("create LLVM Context failed.");
+        goto fail;
+    }
+
+    /* Wrap the LLVM context in a thread safe context. */
+    comp_ctx->orc_thread_safe_context =
+        LLVMOrcCreateNewThreadSafeContextFromLLVMContext(comp_ctx->context);
+    if (!comp_ctx->orc_thread_safe_context) {
+        aot_set_last_error(
+            "Create LLVM ThreadSafeContext from LLVMContext failed.");
+        goto fail;
+    }
+#else // LLVM_VERSION_MAJOR < 21
     comp_ctx->orc_thread_safe_context = LLVMOrcCreateNewThreadSafeContext();
     if (!comp_ctx->orc_thread_safe_context) {
         aot_set_last_error("create LLVM ThreadSafeContext failed.");
@@ -2670,6 +2689,7 @@ aot_create_comp_context(const AOTCompData *comp_data, aot_comp_option_t option)
         aot_set_last_error("get context from LLVM ThreadSafeContext failed.");
         goto fail;
     }
+#endif
 
     if (!(comp_ctx->builder = LLVMCreateBuilderInContext(comp_ctx->context))) {
         aot_set_last_error("create LLVM builder failed.");