diff --git a/build_pr_changes.py b/build_pr_changes.py
index 563fcbe..9f65cd7 100755
--- a/build_pr_changes.py
+++ b/build_pr_changes.py
@@ -562,6 +562,16 @@ def check_for_recipe(line, changed_files, changed_recipe, recipes):
             changed_recipe[0] = ""
 
 
+def add_bool_variant(variant, new_variants, line):
+    """Check the variant default and add boolean variants to the list of new variants"""
+
+    default = re.search(r"default=(\w+)", line)
+    # Check the line for "default=False" or "default=True" and if it is a boolean variant:
+    if default and default.group(1) in ("True", "False"):
+        # add the variant to the list of new variants:
+        new_variants.append(variant.group(1))
+
+
 # Of course, this diff parser is not perfect, and should be a class, but it's a start.
 def get_specs_to_check(args) -> List[str]:
     """Check if the current branch is up-to-date with the remote branch.
@@ -580,6 +590,7 @@ def get_specs_to_check(args) -> List[str]:
     next_line_is_version = False
     next_line_is_variant = False
     version_match = None
+    multiline_variant = None
 
     # The most reliable way to get the PR diff is to use the GitHub CLI:
     err, stdout, stderr = run(["gh", "pr", "diff"])
@@ -594,6 +605,7 @@ def get_specs_to_check(args) -> List[str]:
             next_line_is_variant = False
             default_versions = new_versions
             version_match = None
+            multiline_variant = None
             continue
         if line[0] != "+":
             continue
@@ -602,6 +614,12 @@ def get_specs_to_check(args) -> List[str]:
         if not recipe[0]:
             continue
 
+        if multiline_variant:
+            add_bool_variant(variant, new_variants, line)
+            if "    )" in line:
+                multiline_variant = None
+            continue
+
         # Get the list of new and changed versions from the PR diff:
         version_start = re.search(r"    version\($", line)  # version(
         if version_start:
@@ -636,12 +654,12 @@ def get_specs_to_check(args) -> List[str]:
             continue
         variant = re.search(r'    variant\("([^"]+)", ', line)  # variant("name",
         if next_line_is_variant or variant:
-            next_line_is_variant = False
             variant = variant or re.search(r'"([^"]+)"', line)
             if variant:
-                variant_str = variant.group(1)
-                if variant_str not in ["cxxstd", "cuda"]:
-                    new_variants.append(variant_str)
+                if next_line_is_variant:
+                    multiline_variant = variant
+                    next_line_is_variant = False
+                add_bool_variant(variant, new_variants, line)
             continue
 
     add_recipe_variant_version(specs, recipe, new_variants, new_versions, deprecated)
diff --git a/pyproject.toml b/pyproject.toml
index 3307f64..64c77cb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -45,7 +45,7 @@ disable = [
 ]
 # Maximum number of branch for function / method body.
 # defaults to: max-branches=12
-max-branches = 16
+max-branches = 18
 
 # Maximum number of locals for function / method body.
 # defaults to: max-locals=15
@@ -53,7 +53,7 @@ max-locals = 22
 
 # Maximum number of statements in function / method body.
 # defaults to: max-statements=50
-max-statements = 68
+max-statements = 74
 
 # Maximum number of lines in a module.
 # defaults to: max-module-lines=1000