diff --git a/tools/appscript/export-to-github.mjs b/tools/appscript/export-to-github.mjs
index 7b0db32..3510cc9 100644
--- a/tools/appscript/export-to-github.mjs
+++ b/tools/appscript/export-to-github.mjs
@@ -1,10 +1,13 @@
 import { getProject } from './project.mjs';
 import reportError from './report-error.mjs';
+import { fetchProjectFromGitHub, saveSessionMeetings } from '../common/project.mjs';
+
 
 /**
  * Trigger a GitHub workflow that refreshes the data from GitHub
  */
-export default function () {
+export default async function () {
+  // TODO: consider reading only the list of sessions
   const project = getProject(SpreadsheetApp.getActiveSpreadsheet());
 
   if (!project.metadata.reponame) {
@@ -21,5 +24,89 @@ If not, ask François or Ian to run the required initialization steps.`);
     owner: repoparts.length > 1 ? repoparts[0] : 'w3c',
     name: repoparts.length > 1 ? repoparts[1] : repoparts[0]
   };
+
+  let githubProject;
+  try {
+    githubProject = await fetchProjectFromGitHub(
+      repo.owner === 'w3c' ? repo.owner : `user/${repo.owner}`,
+      repo.name,
+      null
+    );
+  }
+  catch (err) {
+    reportError(err.toString());
+    return;
+  }
+
+  const updated = [];
+  try {
+    // Check sessions that need an update
+    for (const session of githubProject.sessions) {
+      const ssSession = project.sessions.find(s =>
+        s.number === session.number);
+      if (!ssSession) {
+        const htmlOutput = HtmlService
+          .createHtmlOutput(`
+            <p>Sorry, I did not export anything because I detected a new
+            session in the GitHub repository that is not in the spreadsheet yet:
+            </p>
+            <blockquote>
+              <p>${session.title}
+              (<a href="https://github.com/${session.repository}/issues/${session.number}">#${session.number}</a>)
+              </p>
+            </blockquote>
+            <p>Please run <b>TPAC > Sync with GitHub > Import data from GitHub</b>
+            first to retrieve it.
+            You may also want to re-validate the grid afterwards!</p>`
+          )
+          .setWidth(400)
+          .setHeight(400);
+        SpreadsheetApp.getUi().showModalDialog(htmlOutput, 'Not up-to-date!');
+        return;
+      }
+
+      // TODO: handle meeting column for TPAC group meetings
+
+      if ((session.room !== ssSession.room) ||
+          (session.day !== ssSession.day) ||
+          (session.slot !== ssSession.slot)) {
+        console.warn(`- updating #${session.number}...`);
+        session.room = ssSession.room;
+        session.day = ssSession.day;
+        session.slot = ssSession.slot;
+        await saveSessionMeetings(session, githubProject);
+        updated.push(session);
+        console.warn(`- updating #${session.number}... done`);
+      }
+    }
+  }
+  catch(err) {
+    reportError(err.toString());
+    return;
+  }
   
+  // Report the list of sessions that were updated
+  if (updated.length > 0) {
+    const list = updated.map(s =>
+      `${s.title} (<a href="https://github.com/${s.repository}/issues/${s.number}">#${s.number}</a>)`);
+    const htmlOutput = HtmlService
+      .createHtmlOutput(`
+        <p>The following session${list.length > 1 ? 's were' : ' was'} updated:</p>
+        <ul>
+          <li>${list.join('</li><li>')}</li>
+        </ul>`
+      )
+      .setWidth(400)
+      .setHeight(400);
+    SpreadsheetApp.getUi().showModalDialog(htmlOutput, 'Updated');
+  }
+  else {
+    const htmlOutput = HtmlService
+      .createHtmlOutput(`
+        <p>Data seems up-to-date already, nothing to export!</p>`
+      )
+      .setWidth(400)
+      .setHeight(400);
+    SpreadsheetApp.getUi().showModalDialog(htmlOutput, 'Nothing to update');
+  }
 }
\ No newline at end of file
diff --git a/tools/appscript/project.mjs b/tools/appscript/project.mjs
index a4bef32..f33a1d9 100644
--- a/tools/appscript/project.mjs
+++ b/tools/appscript/project.mjs
@@ -212,9 +212,8 @@ export function getProject(spreadsheet) {
     // TODO: how to retrieve the labels?
     labels: [],
 
-    // TODO: initialize from sessions sheet if it exists
     // TODO: complete with meetings sheet if it exists
-    sessions: []
+    sessions: sheets.sessions.values
   };
 
   return project;
diff --git a/tools/common/project.mjs b/tools/common/project.mjs
index 4872e6e..264ded3 100644
--- a/tools/common/project.mjs
+++ b/tools/common/project.mjs
@@ -576,4 +576,51 @@ export function convertProjectToJSON(project) {
     return simplified;
   });
   return data;
-}
\ No newline at end of file
+}
+
+
+/**
+ * Record the meetings assignments for the provided session
+ */
+export async function saveSessionMeetings(session, project, options) {
+  // Project may not have some of the custom fields, and we may only
+  // be interested in a restricted set of them
+  const fields = ['room', 'day', 'slot', 'meeting', 'trymeout', 'registrants']
+    .filter(field => project[field + 'sFieldId'])
+    .filter(field => !options || !options.fields || options.fields.includes(field));
+  for (const field of fields) {
+    const prop = ['meeting', 'trymeout', 'registrants'].includes(field) ?
+      'text': 'singleSelectOptionId';
+    let value = null;
+    if (prop === 'text') {
+      // Text field
+      if (session[field]) {
+        value = `"${session[field]}"`;
+      }
+    }
+    else {
+      // Option in a selection field
+      const obj = project[field + 's'].find(o => o.name === session[field]);
+      if (obj) {
+        value = `"${obj.id}"`;
+      }
+    }
+    const resField = await sendGraphQLRequest(`mutation {
+      updateProjectV2ItemFieldValue(input: {
+        clientMutationId: "mutatis mutandis",
+        fieldId: "${project[field + 'sFieldId']}",
+        itemId: "${session.projectItemId}",
+        projectId: "${project.id}",
+        value: {
+          ${prop}: ${value}
+        }
+      }) {
+        clientMutationId
+      }
+    }`);
+    if (!resField?.data?.updateProjectV2ItemFieldValue?.clientMutationId) {
+      console.log(JSON.stringify(resField, null, 2));
+      throw new Error(`GraphQL error, could not assign session #${session.number} to ${field} value "${session[field]}"`);
+    }
+  }
+}
diff --git a/tools/node/lib/project.mjs b/tools/node/lib/project.mjs
index c2f8129..6663226 100644
--- a/tools/node/lib/project.mjs
+++ b/tools/node/lib/project.mjs
@@ -76,53 +76,6 @@ export async function fetchProject(login, id) {
 }
 
 
-/**
- * Record the meetings assignments for the provided session
- */
-export async function saveSessionMeetings(session, project, options) {
-  // Project may not have some of the custom fields, and we may only
-  // be interested in a restricted set of them
-  const fields = ['room', 'day', 'slot', 'meeting', 'trymeout', 'registrants']
-    .filter(field => project[field + 'sFieldId'])
-    .filter(field => !options || !options.fields || options.fields.includes(field));
-  for (const field of fields) {
-    const prop = ['meeting', 'trymeout', 'registrants'].includes(field) ?
-      'text': 'singleSelectOptionId';
-    let value = null;
-    if (prop === 'text') {
-      // Text field
-      if (session[field]) {
-        value = `"${session[field]}"`;
-      }
-    }
-    else {
-      // Option in a selection field
-      const obj = project[field + 's'].find(o => o.name === session[field]);
-      if (obj) {
-        value = `"${obj.id}"`;
-      }
-    }
-    const resField = await sendGraphQLRequest(`mutation {
-      updateProjectV2ItemFieldValue(input: {
-        clientMutationId: "mutatis mutandis",
-        fieldId: "${project[field + 'sFieldId']}",
-        itemId: "${session.projectItemId}",
-        projectId: "${project.id}",
-        value: {
-          ${prop}: ${value}
-        }
-      }) {
-        clientMutationId
-      }
-    }`);
-    if (!resField?.data?.updateProjectV2ItemFieldValue?.clientMutationId) {
-      console.log(JSON.stringify(resField, null, 2));
-      throw new Error(`GraphQL error, could not assign session #${session.number} to ${field} value "${session[field]}"`);
-    }
-  }
-}
-
-
 /**
  * Record session validation problems
  */
diff --git a/tools/node/schedule.mjs b/tools/node/schedule.mjs
index 4bff47e..ab0a02c 100644
--- a/tools/node/schedule.mjs
+++ b/tools/node/schedule.mjs
@@ -1,6 +1,6 @@
 import { readFile } from 'fs/promises';
 import { convertProjectToHTML } from './lib/project2html.mjs';
-import { saveSessionMeetings } from './lib/project.mjs';
+import { saveSessionMeetings } from '../common/project.mjs';
 import { parseMeetingsChanges, applyMeetingsChanges } from './lib/meetings.mjs';
 import { validateGrid } from '../common/validate.mjs';
 import { suggestSchedule } from '../common/schedule.mjs';
diff --git a/tools/node/try-changes.mjs b/tools/node/try-changes.mjs
index 7a19105..ea641a9 100644
--- a/tools/node/try-changes.mjs
+++ b/tools/node/try-changes.mjs
@@ -1,5 +1,5 @@
 import { validateGrid } from '../common/validate.mjs';
-import { saveSessionMeetings } from './lib/project.mjs';
+import { saveSessionMeetings } from '../common/project.mjs';
 import { convertProjectToHTML } from './lib/project2html.mjs';
 
 export default async function (project, options) {
diff --git a/tools/node/view-registrants.mjs b/tools/node/view-registrants.mjs
index 9962d7c..8650a1d 100644
--- a/tools/node/view-registrants.mjs
+++ b/tools/node/view-registrants.mjs
@@ -2,7 +2,7 @@ import puppeteer from 'puppeteer';
 import { validateSession } from '../common/validate.mjs';
 import { authenticate } from './lib/calendar.mjs';
 import { getEnvKey } from '../common/envkeys.mjs';
-import { saveSessionMeetings } from './lib/project.mjs';
+import { saveSessionMeetings } from '../common/project.mjs';
 import { parseSessionMeetings } from '../common/meetings.mjs';
 
 export default async function (project, number, options) {