diff --git a/.drone.star b/.drone.star
index 369f62e..1876080 100644
--- a/.drone.star
+++ b/.drone.star
@@ -9,7 +9,7 @@
 # As the yaml syntax for Drone CI is rather limited.
 
 # Base environment for all jobs
-globalenv={'B2_VARIANT': 'release'}
+globalenv={'UBUNTU_TOOLCHAIN_DISABLE': 'true', 'B2_VARIANT': 'release'}
 
 # Wrapper function to apply the globalenv to all jobs
 def job(
@@ -28,11 +28,11 @@ def main(ctx):
     job(compiler='clang-3.9', cxxstd='11,14',          os='ubuntu-18.04'),
     job(compiler='clang-4.0', cxxstd='11,14',          os='ubuntu-18.04'),
     job(compiler='clang-5.0', cxxstd='11,14,1z',       os='ubuntu-18.04'),
-    job(compiler='clang-6.0', cxxstd='11,14,17',       os='ubuntu-18.04'),
-    job(compiler='clang-7',   cxxstd='11,14,17',       os='ubuntu-18.04'),
-    job(compiler='clang-8',   cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
-    job(compiler='clang-9',   cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
-    job(compiler='clang-10',  cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='clang-6.0', cxxstd='11,14,17',       os='ubuntu-20.04'),
+    job(compiler='clang-7',   cxxstd='11,14,17',       os='ubuntu-20.04'),
+    job(compiler='clang-8',   cxxstd='11,14,17,2a',    os='ubuntu-20.04'),
+    job(compiler='clang-9',   cxxstd='11,14,17,2a',    os='ubuntu-20.04'),
+    job(compiler='clang-10',  cxxstd='11,14,17,2a',    os='ubuntu-20.04'),
     job(compiler='clang-11',  cxxstd='11,14,17,2a',    os='ubuntu-22.04'),
     job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-22.04'),
     job(compiler='clang-13',  cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
@@ -46,7 +46,7 @@ def main(ctx):
     job(compiler='gcc-6',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
     job(compiler='gcc-7',     cxxstd='11,14,1z',       os='ubuntu-18.04'),
     job(compiler='gcc-8',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
-    job(compiler='gcc-9',     cxxstd='11,14,17,2a',    os='ubuntu-18.04'),
+    job(compiler='gcc-9',     cxxstd='11,14,17,2a',    os='ubuntu-20.04'),
     job(compiler='gcc-10',    cxxstd='11,14,17,20',    os='ubuntu-22.04'),
     job(compiler='gcc-11',    cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
     job(compiler='gcc-12',    cxxstd='11,14,17,20,2b', os='ubuntu-22.04'),
@@ -99,10 +99,10 @@ def main(ctx):
     job(compiler='clang',     cxxstd='11,14,17,20,2b', os='osx-xcode-15.0.1'),
     # ARM64
     job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='arm64', add_llvm=True),
-    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='arm64'),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-22.04', arch='arm64'),
     # S390x
     job(compiler='clang-12',  cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='s390x', add_llvm=True),
-    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-20.04', arch='s390x'),
+    job(compiler='gcc-11',    cxxstd='11,14,17,20',    os='ubuntu-22.04', arch='s390x'),
     # Windows
     job(compiler='msvc-14.0', cxxstd=None,              os='windows', env={'B2_DONT_EMBED_MANIFEST': 1}),
     job(compiler='msvc-14.1', cxxstd=None,              os='windows'),