diff --git a/.appveyor.yml b/.appveyor.yml
index ee3d27ad3..495d90afb 100644
--- a/.appveyor.yml
+++ b/.appveyor.yml
@@ -2,7 +2,7 @@ version: 1.6.x-{build}
 
 branches:
   except:
-    - /libpng[0-1][0-7]/
+    - /libpng[0-1][0-8]/
     - /v[0-1][.][0-7][.][0-9]+/
 
 image:
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index b41c10328..ddc483d99 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -4,9 +4,11 @@ on:
   push:
     branches:
       - libpng16
+      - libpng18
   pull_request:
     branches:
       - libpng16
+      - libpng18
 
 jobs:
   lint:
diff --git a/.travis.yml b/.travis.yml
index f14e7c1ca..5b3369e25 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,6 +1,6 @@
 branches:
   except:
-    - /libpng[0-1][0-7]/
+    - /libpng[0-1][0-8]/
     - /v[0-1][.][0-7][.][0-9]+/
 
 language: c
diff --git a/ci/ci_verify_version.sh b/ci/ci_verify_version.sh
index c8ed22506..3203b201f 100755
--- a/ci/ci_verify_version.sh
+++ b/ci/ci_verify_version.sh
@@ -101,11 +101,11 @@ function ci_verify_version {
         else
             ci_err "mismatched: \$PNG_LIBPNG_VER_BUILD -eq 0"
         fi
-        if [[ $PNG_LIBPNG_BUILD_BASE_TYPE -eq $PNG_LIBPNG_BUILD_BETA ]]
+        if [[ $PNG_LIBPNG_BUILD_BASE_TYPE -ne $PNG_LIBPNG_BUILD_STABLE ]]
         then
-            ci_info "matched: \$PNG_LIBPNG_BUILD_BASE_TYPE -eq \$PNG_LIBPNG_BUILD_BETA"
+            ci_info "matched: \$PNG_LIBPNG_BUILD_BASE_TYPE -ne \$PNG_LIBPNG_BUILD_STABLE"
         else
-            ci_err "mismatched: \$PNG_LIBPNG_BUILD_BASE_TYPE -ne \$PNG_LIBPNG_BUILD_BETA"
+            ci_err "mismatched: \$PNG_LIBPNG_BUILD_BASE_TYPE -eq \$PNG_LIBPNG_BUILD_STABLE"
         fi
     else
         ci_err "unexpected: \$PNG_LIBPNG_VER_STRING == '$PNG_LIBPNG_VER_STRING'"