diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index bd3c03487..ac5c82429 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -331,6 +331,7 @@ a hard error in the future.''' % name)
             myid = subdir_part + '@@' + myid
         return myid
 
+    @FeatureNewKwargs('build target', '0.41.0', ['rust_args'])
     @FeatureNewKwargs('build target', '0.40.0', ['build_by_default'])
     def process_kwargs(self, kwargs):
         if 'build_by_default' in kwargs:
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 55faddc9f..379afca59 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -2861,6 +2861,8 @@ root and issuing %s.
     def func_vcs_tag(self, node, args, kwargs):
         if 'input' not in kwargs or 'output' not in kwargs:
             raise InterpreterException('Keyword arguments input and output must exist')
+        if 'fallback' not in kwargs:
+            FeatureNew('Optional fallback in vcs_tag', '0.41.0').use()
         fallback = kwargs.pop('fallback', self.project_version)
         if not isinstance(fallback, str):
             raise InterpreterException('Keyword argument fallback must be a string.')
@@ -3174,6 +3176,7 @@ root and issuing %s.
         self.build.install_dirs.append(idir)
         return idir
 
+    @FeatureNewKwargs('configure_file', '0.41.0', ['capture'])
     @permittedKwargs(permitted_kwargs['configure_file'])
     def func_configure_file(self, node, args, kwargs):
         if len(args) > 0:
diff --git a/mesonbuild/modules/pkgconfig.py b/mesonbuild/modules/pkgconfig.py
index 365d3cd37..c138ad8dc 100644
--- a/mesonbuild/modules/pkgconfig.py
+++ b/mesonbuild/modules/pkgconfig.py
@@ -21,7 +21,7 @@ from .. import mesonlib
 from .. import mlog
 from . import ModuleReturnValue
 from . import ExtensionModule
-from ..interpreterbase import permittedKwargs
+from ..interpreterbase import permittedKwargs, FeatureNewKwargs, FeatureNew
 
 class DependenciesHelper:
     def __init__(self, name):
@@ -304,10 +304,13 @@ class PkgConfigModule(ExtensionModule):
                 ofile.write(self._escape(f))
             ofile.write('\n')
 
+    @FeatureNewKwargs('pkgconfig.generate', '0.41.0', ['variables'])
     @permittedKwargs({'libraries', 'version', 'name', 'description', 'filebase',
                       'subdirs', 'requires', 'requires_private', 'libraries_private',
                       'install_dir', 'extra_cflags', 'variables', 'url', 'd_module_versions'})
     def generate(self, state, args, kwargs):
+        if 'variables' in kwargs:
+            FeatureNew('custom pkgconfig variables', '0.41.0').use()
         default_version = state.project_version['version']
         default_install_dir = None
         default_description = None