diff --git a/.github/workflows/lock.yml b/.github/workflows/lock.yml
index 5ed1e8ee84..4a4d2057db 100644
--- a/.github/workflows/lock.yml
+++ b/.github/workflows/lock.yml
@@ -1,29 +1,129 @@
-name: 'Lock Threads'
+name: Close old issues and pull requests
 
 on:
   schedule:
     - cron: '0 6 * * *'
+  workflow_dispatch:
+
+concurrency:
+  group: close-old-threads
+  cancel-in-progress: false
 
 permissions:
-  contents: read
+  issues: write
+  pull-requests: write
 
 jobs:
-  lock:
-    permissions:
-      issues: write
-      pull-requests: write
+  close-old-threads:
     runs-on: ubuntu-latest
+
     steps:
-      - uses: dessant/lock-threads@v2.0.1
+      - uses: actions/github-script@v9
         with:
-          github-token: ${{ github.token }}
-          issue-lock-inactive-days: '30'
-          issue-lock-comment: >
-            This issue has been automatically locked. To avoid confusion
-            with reports that have already been resolved, closed issues
-            are automatically locked 30 days after the last comment.
-            Please open a new issue for related bugs.
-          pr-lock-comment: >
-            This pull request has been automatically locked.
-            Pull requests that have been closed are automatically
-            locked 30 days after the last comment.
+          script: |
+            const cutoffDays = 30;
+            const exemptLabels = ['keep-open'];
+
+            const cutoff = new Date();
+            cutoff.setDate(cutoff.getDate() - cutoffDays);
+
+            const closeIssueMessage = [
+              'This issue has been automatically closed and locked.',
+              '',
+              'Processing 3.x is no longer actively developed. Since January 2020, development moved to the Processing 4 repository.',
+              '',
+              "If this issue is still relevant to Processing 4, we'd love to hear from you. Please open a new issue at:",
+              'https://github.com/processing/processing4/issues/new/choose',
+              '',
+              'Thank you for helping improve Processing.'
+            ].join('\n');
+
+            const closePrMessage = [
+              'This pull request has been automatically closed and locked.',
+              '',
+              'Processing 3.x is no longer actively developed. Since January 2020, development moved to the Processing 4 repository.',
+              '',
+              "If you'd still like to contribute this work, please open an issue in the Processing 4 repository to discuss it first:",
+              'https://github.com/processing/processing4/issues/new/choose',
+              '',
+              'Thank you for your contribution.'
+            ].join('\n');
+
+            async function closeThread(thread) {
+              const isPr = Boolean(thread.pull_request);
+
+              if (isPr) {
+                await github.rest.pulls.update({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  pull_number: thread.number,
+                  state: 'closed'
+                });
+              } else {
+                await github.rest.issues.update({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  issue_number: thread.number,
+                  state: 'closed',
+                  state_reason: 'not_planned'
+                });
+              }
+            }
+
+            const threads = await github.paginate(github.rest.issues.listForRepo, {
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              state: 'open',
+              per_page: 100,
+              sort: 'updated',
+              direction: 'asc'
+            });
+
+            for (const thread of threads) {
+              try {
+                const updatedAt = new Date(thread.updated_at);
+
+                if (updatedAt > cutoff) {
+                  break;
+                }
+
+                const labels = thread.labels.map(label =>
+                  typeof label === 'string' ? label : label.name
+                );
+
+                const isExempt = labels.some(label => exemptLabels.includes(label));
+
+                if (isExempt) {
+                  console.log(`Skipping #${thread.number}: exempt label.`);
+                  continue;
+                }
+
+                const isPr = Boolean(thread.pull_request);
+                const body = isPr ? closePrMessage : closeIssueMessage;
+
+                await closeThread(thread);
+
+                if (thread.locked) {
+                  console.log(`Closed #${thread.number}: already locked, so no comment was added.`);
+                  continue;
+                }
+
+                await github.rest.issues.createComment({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  issue_number: thread.number,
+                  body
+                });
+
+                await github.rest.issues.lock({
+                  owner: context.repo.owner,
+                  repo: context.repo.repo,
+                  issue_number: thread.number,
+                  lock_reason: 'resolved'
+                });
+
+                console.log(`Closed and locked #${thread.number}.`);
+              } catch (error) {
+                console.log(`Failed on #${thread.number}: ${error.status || 'unknown status'} ${error.message}`);
+              }
+            }