From f7dad729e4b776ec0ea7171d7e9163045764b060 Mon Sep 17 00:00:00 2001
From: Ferdinand Thiessen <opensource@fthiessen.de>
Date: Thu, 15 Jan 2026 00:28:07 +0100
Subject: [PATCH] refactor(core): migrate web updater to Vue

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>
---
 build/frontend-legacy/webpack.modules.cjs |   1 +
 core/ajax/update.php                      |   1 -
 core/js/update.js                         | 160 -----------
 core/src/update.ts                        |  20 ++
 core/src/views/UpdaterAdmin.vue           | 317 ++++++++++++++++++++++
 core/src/views/UpdaterAdminCli.vue        |  53 ++++
 core/templates/update.admin.php           |  60 ----
 core/templates/update.php                 |   8 +
 core/templates/update.use-cli.php         |  32 ---
 lib/base.php                              |  77 ++++--
 10 files changed, 452 insertions(+), 277 deletions(-)
 delete mode 100644 core/js/update.js
 create mode 100644 core/src/update.ts
 create mode 100644 core/src/views/UpdaterAdmin.vue
 create mode 100644 core/src/views/UpdaterAdminCli.vue
 delete mode 100644 core/templates/update.admin.php
 create mode 100644 core/templates/update.php
 delete mode 100644 core/templates/update.use-cli.php

diff --git a/build/frontend-legacy/webpack.modules.cjs b/build/frontend-legacy/webpack.modules.cjs
index 43405d97de0..a68a7a0e2da 100644
--- a/build/frontend-legacy/webpack.modules.cjs
+++ b/build/frontend-legacy/webpack.modules.cjs
@@ -29,6 +29,7 @@ module.exports = {
 		public: path.join(__dirname, 'core/src', 'public.ts'),
 		public_share_auth: path.join(__dirname, 'core/src', 'public-share-auth.ts'),
 		'twofactor-request-token': path.join(__dirname, 'core/src', 'twofactor-request-token.ts'),
+		update: path.join(__dirname, 'core/src', 'update.ts'),
 	},
 	dashboard: {
 		main: path.join(__dirname, 'apps/dashboard/src', 'main.js'),
diff --git a/core/ajax/update.php b/core/ajax/update.php
index 22bbdcff3e0..0a882929537 100644
--- a/core/ajax/update.php
+++ b/core/ajax/update.php
@@ -106,7 +106,6 @@ if (Util::needUpgrade()) {
 	});
 	$updater->listen('\OC\Updater', 'failure', function ($message) use ($eventSource, $config): void {
 		$eventSource->send('failure', $message);
-		$eventSource->close();
 		$config->setSystemValue('maintenance', false);
 	});
 	$updater->listen('\OC\Updater', 'setDebugLogLevel', function ($logLevel, $logLevelName) use ($eventSource, $l): void {
diff --git a/core/js/update.js b/core/js/update.js
deleted file mode 100644
index 382ad8414ac..00000000000
--- a/core/js/update.js
+++ /dev/null
@@ -1,160 +0,0 @@
-/**
- * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
- * SPDX-FileCopyrightText: 2014 ownCloud Inc.
- * SPDX-License-Identifier: AGPL-3.0-or-later
- */
-
-(function() {
-	OC.Update = {
-		_started: false,
-		options: {},
-
-		/**
-		 * Start the update process.
-		 *
-		 * @param $el progress list element
-		 * @param options
-		 */
-		start: function($el, options) {
-			if (this._started) {
-				return
-			}
-
-			this.options = options
-			let hasWarnings = false
-
-			this.$el = $el
-
-			this._started = true
-
-			const self = this
-
-			$(window).on('beforeunload.inprogress', function() {
-				return t('core', 'The update is in progress, leaving this page might interrupt the process in some environments.')
-			})
-
-			$('#update-progress-title').html(t(
-				'core',
-				'Update to {version}',
-				{
-					version: options.version,
-				},
-			))
-
-			const updateEventSource = new OC.EventSource(OC.getRootPath() + '/core/ajax/update.php')
-			updateEventSource.listen('success', function(message) {
-				self.setMessage(message)
-			})
-			updateEventSource.listen('notice', function(message) {
-				self.setPermanentMessage(message)
-				hasWarnings = true
-			})
-			updateEventSource.listen('error', function(message) {
-				$('#update-progress-message').hide()
-				$('#update-progress-icon')
-					.addClass('icon-error-white')
-					.removeClass('icon-loading-dark')
-				message = message || t('core', 'An error occurred.')
-				$(window).off('beforeunload.inprogress')
-				self.setErrorMessage(message)
-				message = t('core', 'Please reload the page.')
-				$('<p>').append('<a href=".">' + message + '</a>').appendTo($el)
-				updateEventSource.close()
-			})
-			updateEventSource.listen('failure', function(message) {
-				$(window).off('beforeunload.inprogress')
-				$('#update-progress-message').hide()
-				$('#update-progress-icon')
-					.addClass('icon-error-white')
-					.removeClass('icon-loading-dark')
-
-				self.setErrorMessage(message)
-				const updateUnsuccessful = $('<p>')
-				if (message === 'Exception: Updates between multiple major versions and downgrades are unsupported.') {
-					updateUnsuccessful.append(t('core', 'The update was unsuccessful. For more information <a href="{url}">check our forum post</a> covering this issue.', { url: 'https://help.nextcloud.com/t/updates-between-multiple-major-versions-are-unsupported/7094' }))
-				} else if (OC.Update.options.productName === 'Nextcloud') {
-					updateUnsuccessful.append(t('core', 'The update was unsuccessful. '
-					+ 'Please report this issue to the '
-					+ '<a href="https://github.com/nextcloud/server/issues" target="_blank">Nextcloud community</a>.'))
-				}
-				updateUnsuccessful.appendTo($el)
-			})
-			updateEventSource.listen('done', function() {
-				$(window).off('beforeunload.inprogress')
-
-				$('#update-progress-message').hide()
-
-				$('#update-progress-icon')
-					.addClass('icon-checkmark-white')
-					.removeClass('icon-loading-dark')
-
-				if (hasWarnings) {
-					$el.find('.update-show-detailed').before($('<input type="button" class="primary" value="' + t('core', 'Continue to {productName}', OC.Update.options) + '">').on('click', function() {
-						window.location.reload()
-					}))
-				} else {
-					$el.find('.update-show-detailed').before($('<p id="redirect-countdown"></p>'))
-
-					for (let i = 0; i <= 4; i++) {
-						self.updateCountdown(i, 4)
-					}
-
-					setTimeout(function() {
-						window.location = window.location.href
-						window.location.reload()
-					}, 3000)
-				}
-			})
-		},
-
-		updateCountdown: function(i, total) {
-			setTimeout(function() {
-				$('#redirect-countdown').text(n('core', 'The update was successful. Redirecting you to {productName} in %n second.', 'The update was successful. Redirecting you to {productName} in %n seconds.', i, OC.Update.options))
-			}, (total - i) * 1000)
-		},
-
-		setMessage: function(message) {
-			$('#update-progress-message').html(message)
-			$('#update-progress-detailed')
-				.append('<p>' + message + '</p>')
-		},
-
-		setPermanentMessage: function(message) {
-			$('#update-progress-message').html(message)
-			$('#update-progress-message-warnings')
-				.show()
-				.append($('<ul>').append(message))
-			$('#update-progress-detailed')
-				.append('<p>' + message + '</p>')
-		},
-
-		setErrorMessage: function(message) {
-			$('#update-progress-message-error')
-				.show()
-				.html(message)
-			$('#update-progress-detailed')
-				.append('<p>' + message + '</p>')
-		},
-	}
-})()
-
-window.addEventListener('DOMContentLoaded', function() {
-	$('.updateButton').on('click', function() {
-		const $updateEl = $('.update')
-		const $progressEl = $('.update-progress')
-		$progressEl.removeClass('hidden')
-		$('.updateOverview').addClass('hidden')
-		$('#update-progress-message-error').hide()
-		$('#update-progress-message-warnings').hide()
-		OC.Update.start($progressEl, {
-			productName: $updateEl.attr('data-productname'),
-			version: $updateEl.attr('data-version'),
-		})
-		return false
-	})
-
-	$('.update-show-detailed').on('click', function() {
-		$('#update-progress-detailed').toggleClass('hidden')
-		return false
-	})
-})
diff --git a/core/src/update.ts b/core/src/update.ts
new file mode 100644
index 00000000000..a3f95431984
--- /dev/null
+++ b/core/src/update.ts
@@ -0,0 +1,20 @@
+/*!
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+import { getCSPNonce } from '@nextcloud/auth'
+import { loadState } from '@nextcloud/initial-state'
+import Vue, { defineAsyncComponent } from 'vue'
+
+__webpack_nonce__ = getCSPNonce()
+
+const UpdaterAdmin = defineAsyncComponent(() => import('./views/UpdaterAdmin.vue'))
+const UpdaterAdminCli = defineAsyncComponent(() => import('./views/UpdaterAdminCli.vue'))
+
+const view = loadState('core', 'updaterView')
+const app = new Vue({
+	name: 'NextcloudUpdater',
+	render: (h) => view === 'adminCli' ? h(UpdaterAdminCli) : h(UpdaterAdmin),
+})
+app.$mount('#core-updater')
diff --git a/core/src/views/UpdaterAdmin.vue b/core/src/views/UpdaterAdmin.vue
new file mode 100644
index 00000000000..9197707b0ce
--- /dev/null
+++ b/core/src/views/UpdaterAdmin.vue
@@ -0,0 +1,317 @@
+<!--
+  - SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
+<script setup lang="ts">
+import {
+	mdiAlertCircleOutline,
+	mdiCheckCircleOutline,
+	mdiChevronDown,
+	mdiChevronUp,
+	mdiCloseCircleOutline,
+	mdiInformationOutline,
+} from '@mdi/js'
+import { loadState } from '@nextcloud/initial-state'
+import { t } from '@nextcloud/l10n'
+import { generateFilePath } from '@nextcloud/router'
+import { NcButton, NcIconSvgWrapper, NcLoadingIcon } from '@nextcloud/vue'
+import { computed, onMounted, onUnmounted, ref } from 'vue'
+import NcGuestContent from '@nextcloud/vue/components/NcGuestContent'
+import NcNoteCard from '@nextcloud/vue/components/NcNoteCard'
+import OCEventSource from '../OC/eventsource.js'
+
+const updateInfo = loadState<{
+	appsToUpgrade: { id: string, name: string, version: string, oldVersion: string }[]
+	incompatibleAppsList: { id: string, name: string }[]
+	isAppsOnlyUpgrade: boolean
+	oldTheme: string | null
+	productName: string
+	version: string
+}>('core', 'updateInfo')
+
+const isShowingDetails = ref(false)
+const isUpdateRunning = ref(false)
+const isUpdateDone = ref(false)
+
+const messages = ref<{ message: string, type: string }[]>([])
+const wasSuccessfull = computed(() => messages.value.every((msg) => msg.type === 'success' || msg.type === 'notice'))
+const hasErrors = computed(() => messages.value.some((msg) => msg.type === 'error' || msg.type === 'failure'))
+const resultIcon = computed(() => wasSuccessfull.value ? mdiCheckCircleOutline : (hasErrors.value ? mdiCloseCircleOutline : mdiAlertCircleOutline))
+
+const statusMessage = computed(() => {
+	if (isUpdateDone.value) {
+		if (!wasSuccessfull.value) {
+			return t('core', 'The update completed with warnings. Please check the details for more information.')
+		} else {
+			return t('core', 'The update completed successfully.')
+		}
+	}
+	return messages.value.at(-1)?.message || t('core', 'Preparing update…')
+})
+
+const redirectCountdown = ref(6)
+const redirectMessage = computed(() => {
+	if (!isUpdateDone.value || !wasSuccessfull.value) {
+		return ''
+	}
+
+	return t('core', 'You will be redirected to {productName} in {count} seconds.', { productName: updateInfo.productName, count: redirectCountdown.value })
+})
+
+onMounted(() => window.addEventListener('beforeunload', onUnload))
+onUnmounted(() => window.removeEventListener('beforeunload', onUnload))
+
+/**
+ * Get the status icon for a given severity
+ *
+ * @param type - The severity
+ */
+function getSeverityIcon(type: string) {
+	switch (type) {
+		case 'success':
+			return mdiCheckCircleOutline
+		case 'notice':
+			return mdiInformationOutline
+		case 'warning':
+			return mdiAlertCircleOutline
+		case 'error':
+		case 'failure':
+			return mdiCloseCircleOutline
+		default:
+			return mdiInformationOutline
+	}
+}
+
+/**
+ * Start the update process
+ */
+async function onStartUpdate() {
+	if (isUpdateRunning.value || isUpdateDone.value) {
+		return
+	}
+
+	isUpdateRunning.value = true
+	const eventSource = new OCEventSource(generateFilePath('core', '', 'ajax/update.php'))
+	eventSource.listen('success', (message) => {
+		messages.value.push({ message, type: 'success' })
+	})
+	eventSource.listen('notice', (message) => {
+		messages.value.push({ message, type: 'notice' })
+	})
+	eventSource.listen('error', (message) => {
+		messages.value.push({ message, type: 'error' })
+		isUpdateRunning.value = false
+		isUpdateDone.value = true
+		eventSource.close()
+	})
+	eventSource.listen('failure', (message) => {
+		messages.value.push({ message, type: 'failure' })
+	})
+	eventSource.listen('done', () => {
+		isUpdateRunning.value = false
+		isUpdateDone.value = true
+		eventSource.close()
+		updateCountdown()
+	})
+}
+
+/**
+ * Update the countdown for the redirect
+ */
+function updateCountdown() {
+	if (hasErrors.value || !wasSuccessfull.value) {
+		return
+	}
+
+	if (--redirectCountdown.value > 0) {
+		window.setTimeout(updateCountdown, 1000)
+	} else {
+		reloadPage()
+	}
+}
+
+/**
+ * Handle the beforeunload event to warn the user if an update is running.
+ *
+ * @param event - The beforeunload event object.
+ */
+function onUnload(event: BeforeUnloadEvent) {
+	if (isUpdateRunning.value) {
+		event.preventDefault()
+		event.returnValue = t('core', 'The update is in progress, leaving this page might interrupt the process in some environments.')
+	}
+}
+
+/**
+ * Reload the page
+ */
+function reloadPage() {
+	window.location.reload()
+}
+</script>
+
+<template>
+	<NcGuestContent>
+		<h2>
+			{{ updateInfo.isAppsOnlyUpgrade
+				? t('core', 'App update required')
+				: t('core', '{productName} will be updated to version {version}', { productName: updateInfo.productName, version: updateInfo.version }) }}
+		</h2>
+
+		<NcNoteCard v-if="!!updateInfo.oldTheme" type="info">
+			{{ t('core', 'The theme {oldTheme} has been disabled.', { oldTheme: updateInfo.oldTheme }) }}
+		</NcNoteCard>
+
+		<NcNoteCard v-if="updateInfo.incompatibleAppsList.length" type="warning">
+			{{ t('core', 'These incompatible apps will be disabled:') }}
+			<ul :aria-label="t('core', 'Incompatible apps')" :class="$style.updater__appsList">
+				<li v-for="app of updateInfo.incompatibleAppsList" :key="'app-disable-' + app.id">
+					{{ app.name }} ({{ app.id }})
+				</li>
+			</ul>
+		</NcNoteCard>
+
+		<NcNoteCard v-if="updateInfo.incompatibleAppsList.length" type="info">
+			{{ t('core', 'These apps will be updated:') }}
+			<ul :aria-label="t('core', 'Apps to update')" :class="$style.updater__appsList">
+				<li v-for="app of updateInfo.appsToUpgrade" :key="'app-update-' + app.id">
+					{{ t('core', '{app} from {oldVersion} to {version}', { app: `${app.name} (${app.id})`, oldVersion: app.oldVersion, version: app.version }) }}
+				</li>
+			</ul>
+		</NcNoteCard>
+
+		<p>
+			<strong>{{ t('core', 'Please make sure that the database, the config folder and the data folder have been backed up before proceeding.') }}</strong>
+			<br>
+			{{ t('core', 'To avoid timeouts with larger installations, you can instead run the following command from your installation directory:') }}
+			<pre>./occ upgrade</pre>
+		</p>
+
+		<NcButton
+			v-if="!isUpdateRunning && !isUpdateDone"
+			:class="$style.updater__updateButton"
+			variant="primary"
+			@click="onStartUpdate">
+			{{ t('core', 'Start update') }}
+		</NcButton>
+		<NcButton
+			v-else
+			:class="$style.updater__updateButton"
+			:disabled="isUpdateRunning"
+			variant="primary"
+			@click="reloadPage">
+			{{ t('core', 'Continue to {productName}', { productName: updateInfo.productName }) }}
+		</NcButton>
+
+		<div v-if="isUpdateRunning || isUpdateDone">
+			<h2>{{ t('core', 'Update to {version}', { version: updateInfo.version }) }}</h2>
+
+			<NcLoadingIcon v-if="isUpdateRunning" />
+			<NcIconSvgWrapper
+				v-else
+				:path="resultIcon"
+				:class="{
+					[$style.updater__messageIcon_success]: wasSuccessfull,
+					[$style.updater__messageIcon_error]: hasErrors && !wasSuccessfull,
+					[$style.updater__messageIcon_warning]: !hasErrors && !wasSuccessfull,
+				}" />
+			<div aria-live="polite">
+				<em>{{ statusMessage }}</em><br>
+				<span v-if="redirectMessage">{{ redirectMessage }}</span>
+			</div>
+
+			<NcButton
+				aria-controlls="core-update-details"
+				:aria-expanded="isShowingDetails"
+				variant="tertiary"
+				@click="isShowingDetails = !isShowingDetails">
+				<template #icon>
+					<NcIconSvgWrapper
+						:path="isShowingDetails ? mdiChevronUp : mdiChevronDown" />
+				</template>
+				{{ isShowingDetails ? t('core', 'Hide details') : t('core', 'Show details') }}
+			</NcButton>
+			<Transition
+				:enter-active-class="$style.updater__transition_active"
+				:leave-active-class="$style.updater__transition_active"
+				:leave-to-class="$style.updater__transition_collapsed"
+				:enter-class="$style.updater__transition_collapsed">
+				<ul
+					v-show="isShowingDetails"
+					id="core-update-details"
+					:aria-label="t('core', 'Update details')"
+					:class="$style.updater__messageList">
+					<li
+						v-for="{ message, type } of messages"
+						:key="message"
+						:class="$style.updater__message">
+						<NcIconSvgWrapper
+							:class="{
+								[$style.updater__messageIcon_error]: type === 'error' || type === 'failure',
+								[$style.updater__messageIcon_info]: type === 'notice',
+								[$style.updater__messageIcon_success]: type === 'success',
+								[$style.updater__messageIcon_warning]: type === 'warning',
+							}"
+							:path="getSeverityIcon(type)" />
+						<span :class="$style.updater__messageText">{{ message }}</span>
+					</li>
+				</ul>
+			</Transition>
+		</div>
+	</NcGuestContent>
+</template>
+
+<style module>
+.updater__appsList {
+	list-style-type: disc;
+	margin-inline-start: var(--default-clickable-area);
+}
+
+.updater__updateButton {
+	margin-inline: auto;
+	margin-block: 1rem;
+}
+
+.updater__messageList {
+	max-height: 50vh;
+	overflow: visible scroll;
+	padding-inline-start: var(--default-grid-baseline);
+}
+
+.updater__message {
+	display: flex;
+	align-items: center;
+	justify-content: start;
+	gap: var(--default-grid-baseline);
+}
+
+.updater__messageText {
+	text-align: start;
+}
+
+.updater__messageIcon_success {
+	color: var(--color-element-success);
+}
+
+.updater__messageIcon_info {
+	color: var(--color-element-info);
+}
+
+.updater__messageIcon_error {
+	color: var(--color-element-error);
+}
+
+.updater__messageIcon_warning {
+	color: var(--color-element-warning);
+}
+
+.updater__transition_active {
+	transition: all var(--animation-slow);
+}
+
+.updater__transition_collapsed {
+	opacity: 0;
+	max-height: 0px;
+}
+</style>
diff --git a/core/src/views/UpdaterAdminCli.vue b/core/src/views/UpdaterAdminCli.vue
new file mode 100644
index 00000000000..092f4b5377d
--- /dev/null
+++ b/core/src/views/UpdaterAdminCli.vue
@@ -0,0 +1,53 @@
+<!--
+  - SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+  - SPDX-License-Identifier: AGPL-3.0-or-later
+-->
+
+<script setup lang="ts">
+import { mdiInformationOutline } from '@mdi/js'
+import { loadState } from '@nextcloud/initial-state'
+import { t } from '@nextcloud/l10n'
+import NcButton from '@nextcloud/vue/components/NcButton'
+import NcGuestContent from '@nextcloud/vue/components/NcGuestContent'
+import NcIconSvgWrapper from '@nextcloud/vue/components/NcIconSvgWrapper'
+import NcNoteCard from '@nextcloud/vue/components/NcNoteCard'
+
+const updateInfo = loadState<{
+	tooBig: boolean
+	cliUpgradeLink: string
+}>('core', 'updateInfo')
+</script>
+
+<template>
+	<NcGuestContent>
+		<h2>{{ t('core', 'Update needed') }}</h2>
+		<p>
+			{{ updateInfo.tooBig
+				? t('core', 'Please use the command line updater because you have a big instance with more than 50 accounts.')
+				: t('core', 'Please use the command line updater because updating via browser is disabled in your config.php.') }}
+
+			<NcButton :class="$style.updaterAdminCli__button" :href="updateInfo.cliUpgradeLink">
+				<template #icon>
+					<NcIconSvgWrapper :path="mdiInformationOutline" />
+				</template>
+				{{ t('core', 'Documentation') }}
+			</NcButton>
+		</p>
+
+		<NcNoteCard type="warning">
+			{{ t('core', 'I know that if I continue doing the update via web UI has the risk, that the request runs into a timeout and could cause data loss, but I have a backup and know how to restore my instance in case of a failure.') }}
+			<NcButton
+				href="?IKnowThatThisIsABigInstanceAndTheUpdateRequestCouldRunIntoATimeoutAndHowToRestoreABackup=IAmSuperSureToDoThis"
+				variant="tertiary">
+				{{ t('core', 'Upgrade via web on my own risk') }}
+			</NcButton>
+		</NcNoteCard>
+	</NcGuestContent>
+</template>
+
+<style module>
+.updaterAdminCli__button {
+	margin-block: 1rem;
+	margin-inline: auto;
+}
+</style>
diff --git a/core/templates/update.admin.php b/core/templates/update.admin.php
deleted file mode 100644
index 504071451a9..00000000000
--- a/core/templates/update.admin.php
+++ /dev/null
@@ -1,60 +0,0 @@
-<?php
-/**
- * SPDX-FileCopyrightText: 2016-2024 Nextcloud GmbH and Nextcloud contributors
- * SPDX-FileCopyrightText: 2013-2015 ownCloud, Inc.
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-?>
-<div class="guest-box update" data-productname="<?php p($_['productName']) ?>" data-version="<?php p($_['version']) ?>">
-	<div class="updateOverview">
-		<?php if ($_['isAppsOnlyUpgrade']) { ?>
-		<h2 class="title"><?php p($l->t('App update required')); ?></h2>
-		<?php } else { ?>
-		<h2 class="title"><?php p($l->t('%1$s will be updated to version %2$s',
-			[$_['productName'], $_['version']])); ?></h2>
-		<?php } ?>
-		<?php if (!empty($_['appsToUpgrade'])) { ?>
-		<div class="text-left">
-			<span><?php p($l->t('The following apps will be updated:')); ?></span>
-			<ul class="content appList">
-				<?php foreach ($_['appsToUpgrade'] as $appInfo) { ?>
-				<li><?php p($appInfo['name']) ?> (<?php p($appInfo['id']) ?>)</li>
-				<?php } ?>
-			</ul>
-		</div>
-		<?php } ?>
-		<?php if (!empty($_['incompatibleAppsList'])) { ?>
-		<div class="text-left">
-			<span><?php p($l->t('These incompatible apps will be disabled:')) ?></span>
-			<ul class="content appList">
-				<?php foreach ($_['incompatibleAppsList'] as $appInfo) { ?>
-				<li><?php p($appInfo['name']) ?> (<?php p($appInfo['id']) ?>)</li>
-				<?php } ?>
-			</ul>
-		</div>
-		<?php } ?>
-		<?php if (!empty($_['oldTheme'])) { ?>
-		<div class="infogroup">
-			<?php p($l->t('The theme %s has been disabled.', [$_['oldTheme']])) ?>
-		</div>
-		<?php } ?>
-		<div class="text-left margin-top bold">
-			<?php p($l->t('Please make sure that the database, the config folder and the data folder have been backed up before proceeding.')) ?>
-		</div>
-		<input class="updateButton primary margin-top" type="button" value="<?php p($l->t('Start update')) ?>">
-		<div class="notecard warning">
-			<?php p($l->t('To avoid timeouts with larger installations, you can instead run the following command from your installation directory:')) ?>
-			<pre>./occ upgrade</pre>
-		</div>
-	</div>
-
-	<div class="update-progress hidden">
-		<h2 id="update-progress-title"></h2>
-		<div id="update-progress-icon" class="icon-loading-dark"></div>
-		<p id="update-progress-message-error" class="hidden"></p>
-		<ul id="update-progress-message-warnings" class="hidden"></ul>
-		<p id="update-progress-message"></p>
-		<a class="update-show-detailed"><?php p($l->t('Detailed logs')); ?> <span class="icon-caret-white"></span></a>
-		<div id="update-progress-detailed" class="hidden"></div>
-	</div>
-</div>
diff --git a/core/templates/update.php b/core/templates/update.php
new file mode 100644
index 00000000000..2e9faab3fed
--- /dev/null
+++ b/core/templates/update.php
@@ -0,0 +1,8 @@
+<?php
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+?>
+
+<div id="core-updater"></div>
diff --git a/core/templates/update.use-cli.php b/core/templates/update.use-cli.php
deleted file mode 100644
index a13dd2f51f1..00000000000
--- a/core/templates/update.use-cli.php
+++ /dev/null
@@ -1,32 +0,0 @@
-<?php
-/**
- * SPDX-FileCopyrightText: 2017-2024 Nextcloud GmbH and Nextcloud contributors
- * SPDX-FileCopyrightText: 2016 ownCloud, Inc.
- * SPDX-License-Identifier: AGPL-3.0-only
- */
-?>
-<div class="guest-box update" data-productname="<?php p($_['productName']) ?>" data-version="<?php p($_['version']) ?>">
-	<div class="updateOverview">
-		<h2 class="title"><?php p($l->t('Update needed')) ?></h2>
-		<div class="text-left">
-			<?php if ($_['tooBig']) {
-				p($l->t('Please use the command line updater because you have a big instance with more than 50 accounts.'));
-			} else {
-				p($l->t('Please use the command line updater because updating via browser is disabled in your config.php.'));
-			} ?><br><br>
-			<?php if (is_string($_['cliUpgradeLink']) && $_['cliUpgradeLink'] !== '') {
-				$cliUpgradeLink = $_['cliUpgradeLink'];
-			} else {
-				$cliUpgradeLink = link_to_docs('admin-cli-upgrade');
-			}
-print_unescaped($l->t('For help, see the  <a target="_blank" rel="noreferrer noopener" href="%s">documentation</a>.', [$cliUpgradeLink])); ?>
-		</div>
-	</div>
-
-	<?php if ($_['tooBig']) { ?>
-		<div class="notecard warning">
-			<p><?php p($l->t('I know that if I continue doing the update via web UI has the risk, that the request runs into a timeout and could cause data loss, but I have a backup and know how to restore my instance in case of a failure.')); ?></p>
-			<a class="button error margin-top" href="?IKnowThatThisIsABigInstanceAndTheUpdateRequestCouldRunIntoATimeoutAndHowToRestoreABackup=IAmSuperSureToDoThis"><?php p($l->t('Upgrade via web on my own risk')); ?></a>
-		</div>
-	<?php } ?>
-</div>
diff --git a/lib/base.php b/lib/base.php
index 632d19968a6..e323e6d2138 100644
--- a/lib/base.php
+++ b/lib/base.php
@@ -17,7 +17,9 @@ use OCP\EventDispatcher\IEventDispatcher;
 use OCP\Files\Events\BeforeFileSystemSetupEvent;
 use OCP\Group\Events\GroupDeletedEvent;
 use OCP\Group\Events\UserRemovedEvent;
+use OCP\IAppConfig;
 use OCP\IConfig;
+use OCP\IInitialStateService;
 use OCP\ILogger;
 use OCP\IRequest;
 use OCP\IURLGenerator;
@@ -290,47 +292,49 @@ class OC {
 		$ignoreTooBigWarning = isset($_GET['IKnowThatThisIsABigInstanceAndTheUpdateRequestCouldRunIntoATimeoutAndHowToRestoreABackup'])
 			&& $_GET['IKnowThatThisIsABigInstanceAndTheUpdateRequestCouldRunIntoATimeoutAndHowToRestoreABackup'] === 'IAmSuperSureToDoThis';
 
+		Util::addTranslations('core');
+		Util::addScript('core', 'common');
+		Util::addScript('core', 'main');
+		Util::addScript('core', 'update');
+
+		$initialState = Server::get(IInitialStateService::class);
+		$serverVersion = \OCP\Server::get(\OCP\ServerVersion::class);
 		if ($disableWebUpdater || ($tooBig && !$ignoreTooBigWarning)) {
 			// send http status 503
 			http_response_code(503);
 			header('Retry-After: 120');
 
-			$serverVersion = \OCP\Server::get(\OCP\ServerVersion::class);
+			$urlGenerator = Server::get(IURLGenerator::class);
+			$initialState->provideInitialState('core', 'updaterView', 'adminCli');
+			$initialState->provideInitialState('core', 'updateInfo', [
+				'cliUpgradeLink' => $cliUpgradeLink ?: $urlGenerator->linkToDocs('admin-cli-upgrade'),
+				'productName' => self::getProductName(),
+				'version' => $serverVersion->getVersionString(),
+				'tooBig' => $tooBig,
+			]);
 
 			// render error page
-			$template = Server::get(ITemplateManager::class)->getTemplate('', 'update.use-cli', 'guest');
-			$template->assign('productName', 'nextcloud'); // for now
-			$template->assign('version', $serverVersion->getVersionString());
-			$template->assign('tooBig', $tooBig);
-			$template->assign('cliUpgradeLink', $cliUpgradeLink);
-
-			$template->printPage();
+			Server::get(ITemplateManager::class)
+				->getTemplate('', 'update', 'guest')
+				->printPage();
 			die();
 		}
 
 		// check whether this is a core update or apps update
 		$installedVersion = $systemConfig->getValue('version', '0.0.0');
-		$currentVersion = implode('.', \OCP\Util::getVersion());
+		$currentVersion = implode('.', $serverVersion->getVersion());
 
 		// if not a core upgrade, then it's apps upgrade
 		$isAppsOnlyUpgrade = version_compare($currentVersion, $installedVersion, '=');
 
 		$oldTheme = $systemConfig->getValue('theme');
 		$systemConfig->setValue('theme', '');
-		\OCP\Util::addScript('core', 'common');
-		\OCP\Util::addScript('core', 'main');
-		\OCP\Util::addTranslations('core');
-		\OCP\Util::addScript('core', 'update');
 
 		/** @var \OC\App\AppManager $appManager */
 		$appManager = Server::get(\OCP\App\IAppManager::class);
 
-		$tmpl = Server::get(ITemplateManager::class)->getTemplate('', 'update.admin', 'guest');
-		$tmpl->assign('version', \OCP\Server::get(\OCP\ServerVersion::class)->getVersionString());
-		$tmpl->assign('isAppsOnlyUpgrade', $isAppsOnlyUpgrade);
-
 		// get third party apps
-		$ocVersion = \OCP\Util::getVersion();
+		$ocVersion = $serverVersion->getVersion();
 		$ocVersion = implode('.', $ocVersion);
 		$incompatibleApps = $appManager->getIncompatibleApps($ocVersion);
 		$incompatibleOverwrites = $systemConfig->getValue('app_install_overwrite', []);
@@ -351,16 +355,41 @@ class OC {
 			throw new \OCP\HintException('Application ' . implode(', ', $incompatibleShippedApps) . ' is not present or has a non-compatible version with this server. Please check the apps directory.', $hint);
 		}
 
-		$tmpl->assign('appsToUpgrade', $appManager->getAppsNeedingUpgrade($ocVersion));
-		$tmpl->assign('incompatibleAppsList', $incompatibleDisabledApps);
+		$appConfig = Server::get(IAppConfig::class);
+		$appsToUpgrade = array_map(function ($app) use (&$appConfig) {
+			return [
+				'id' => $app['id'],
+				'name' => $app['name'],
+				'version' => $app['version'],
+				'oldVersion' => $appConfig->getValueString($app['id'], 'installed_version'),
+			];
+		}, $appManager->getAppsNeedingUpgrade($ocVersion));
+
+		$params = [
+			'appsToUpgrade' => $appsToUpgrade,
+			'incompatibleAppsList' => $incompatibleDisabledApps,
+			'isAppsOnlyUpgrade' => $isAppsOnlyUpgrade,
+			'oldTheme' => $oldTheme,
+			'productName' => self::getProductName(),
+			'version' => $serverVersion->getVersionString(),
+		];
+
+		$initialState->provideInitialState('core', 'updaterView', 'admin');
+		$initialState->provideInitialState('core', 'updateInfo', $params);
+		Server::get(ITemplateManager::class)
+			->getTemplate('', 'update', 'guest')
+			->printPage();
+	}
+
+	private static function getProductName(): string {
+		$productName = 'Nextcloud';
 		try {
 			$defaults = new \OC_Defaults();
-			$tmpl->assign('productName', $defaults->getName());
+			$productName = $defaults->getName();
 		} catch (Throwable $error) {
-			$tmpl->assign('productName', 'Nextcloud');
+			// ignore
 		}
-		$tmpl->assign('oldTheme', $oldTheme);
-		$tmpl->printPage();
+		return $productName;
 	}
 
 	public static function initSession(): void {