Office 2024 and Office 2021 are both one-time purchase versions of Microsoft Office, and they look almost the same at first glance. The real differences are in new Excel and PowerPoint features, the removal of Publisher, and, most importantly, how long Microsoft will keep sending security updates. This guide compares them side by side so you can decide whether to upgrade or stay where you are.
| Point of comparison | Office 2024 / Office LTSC 2024 | Office 2021 / Office LTSC 2021 |
|---|---|---|
| Release (LTSC) | September 2024 | September 2021 |
| Support end date | October 2029 | 13 October 2026 |
| Extended support | None (five years only) | None (five years only) |
| Publisher | Not included | Included in Professional Plus and Standard |
| Teams | Not preinstalled, separate download | No longer included |
| Excel highlights | IMAGE function, dynamic charts, 14 new text and array functions | XLOOKUP, LET, XMATCH, dynamic arrays |
| OpenDocument support | ODF 1.4 | ODF 1.3 |
| Install technology | Click-to-Run | Click-to-Run |
| Major version number | 16.0 | 16.0 |
What is the difference between Office 2024 and Office 2021?
The main difference is the support window, because Office 2021 has a support end date of 13 October 2026 while Office 2024 is supported until October 2029, and Office 2024 also adds new Excel functions, a refreshed design and PowerPoint recording tools while dropping Publisher, although both remain perpetual licences with no subscription.
Underneath, the two versions share the same foundation. Microsoft states that the major version of Office LTSC 2024 is 16.0, the same as Office LTSC 2021, and both install with Click-to-Run rather than the older Windows Installer (MSI) technology.
The advanced nuance is that "Office 2024" covers two product families. Office Home 2024 and Office Home & Business 2024 are consumer editions under the Modern Lifecycle Policy, while Office LTSC Professional Plus 2024 and Office LTSC Standard 2024 are volume-licensed editions under the Fixed Lifecycle Policy. If you are unsure which family your key belongs to, our guide to Office LTSC Standard vs Professional Plus explains the editions.
What is new in Office 2024?
Office 2024 adds a new default Office theme based on Fluent Design, the IMAGE function and dynamic charts in Excel, session recovery in Word, cameo and Recording Studio in PowerPoint, improved search in Outlook for Windows, and support for OpenDocument Format 1.4. None of these changes how documents open; files stay fully compatible with Office 2021.
Microsoft's own list of what's new in Office 2024 and Office LTSC 2024 groups the changes by app. The most useful ones for everyday work are:
- Excel: the IMAGE function places pictures inside cells, dynamic charts update with dynamic array ranges, 14 new text and array functions arrive (TEXTSPLIT is one of them), and workbooks perform faster.
- Word: you can recover your Word session after an unexpected close, react to comments with a Like, and insert a picture from a mobile device.
- PowerPoint: Present with cameo, create a video in Recording Studio, embed Microsoft Stream videos and add closed captions to video and audio.
- Outlook for Windows: improved search across email, calendars and contacts, plus more options when creating meetings.
- Access and OneNote: a Dataverse connector for Power Platform in Access, and an improved Draw tab in OneNote.
Cause and effect matters here: because new functions such as TEXTSPLIT and IMAGE only exist in Excel 2024 and Microsoft 365, a workbook that uses them will show errors when opened in Excel 2021. If you share files with colleagues on newer versions, staying on 2021 can cause formula problems even though the file itself opens.
What was removed or changed in Office 2024?
Office 2024 removes Microsoft Publisher, does not preinstall the Teams app, removes the Publish to Power BI feature from Excel and disables ActiveX controls by default in the LTSC edition, and Publisher is left out because Microsoft is retiring the app, with its support end date set for October 2026.
The Publisher change is the one buyers ask about most. Microsoft's Office LTSC 2024 overview confirms it is not included "due to the planned retirement of Publisher", and Microsoft suggests Word and PowerPoint for tasks such as labels, calendars and business cards.
The ActiveX change can affect older business templates. Administrators can re-enable ActiveX where needed, but if your company relies on legacy forms with embedded controls, test them before rolling out Office 2024 across all PCs.
When does support end for Office 2021 and Office 2024?
Office 2021 and Office LTSC 2021 have a support end date of 13 October 2026 and Office LTSC 2024 is supported until 9 October 2029, because Microsoft gives each LTSC release five years of mainstream support with no extended support, so after those dates there are no security updates, fixes or technical help.
Microsoft's lifecycle page for Office LTSC 2024 lists the start date as September 2024 and the end date in October 2029. The consumer Office 2024 editions, such as Home & Business, also show a retirement date in October 2029.
End of support does not switch the software off. Microsoft says out-of-support Office apps may continue to function, but without security patches they become a growing risk, especially Outlook, which handles email attachments every day. This is the same situation Office 2016 and Office 2019 users have been in since support ended on 14 October 2025.
What are the system requirements for Office 2024 vs Office 2021?
Both versions need a 1.1 GHz or faster dual-core processor, 4 GB of RAM, 4 GB of free disk space and a 1280 x 768 display on Windows, and Microsoft's current requirements list Windows 11 for both, with Office LTSC 2024 also supported on Windows 10 LTSC 2021 and 2019 and Windows Server 2025 and 2022.
On Mac, Microsoft supports Office on the three most recent versions of macOS, with 4 GB of RAM and 10 GB of free disk space, on Intel or Apple silicon. For Arm-based Windows devices, Windows 11 is the minimum supported version.
One practical detail: Microsoft notes that 64-bit Office is required for 4K and higher resolutions. What we commonly see in support is customers choosing 32-bit out of habit, then seeing display problems on high-resolution laptops, so pick 64-bit unless an old add-in specifically needs 32-bit.
Should you upgrade from Office 2021 to Office 2024?
Most people on Office 2021 should plan to upgrade, because Office 2021 security updates stop after 13 October 2026 while Office 2024 is supported until October 2029, although the urgency is lower if you depend on Publisher or run Office on a PC that is never connected to the internet.
Use this quick decision guide:
| Your situation | Suggested choice |
|---|---|
| Home user, documents and spreadsheets, uses Outlook for email | Office 2024, for security updates to 2029 |
| Small business needing Access databases | Office 2024 Professional Plus |
| Heavy Publisher user | Keep Office 2021 for now and plan a move to Word or PowerPoint |
| Shares Excel files with Microsoft 365 users | Office 2024, for the newer functions |
| Still on Office 2016 or 2019 | Skip 2021 and move straight to Office 2024 |
If you decide to move, you can browse the Office 2024 collection or go straight to Office 2024 Professional Plus for Windows. Existing 2021 users can still find keys and guides in the Office 2021 collection, for example to match a version already used across an office.
Can Office 2024 and Office 2021 be installed on the same PC?
You should not run Office 2024 and Office 2021 side by side, because Microsoft does not support two Click-to-Run versions with overlapping apps on one computer, so remove Office 2021 first, restart and then install Office 2024, knowing that uninstalling Office does not delete your documents or spreadsheets.
A second rule causes many install failures: all Office products on one device must use the same update channel. Volume-licensed Office LTSC 2024 uses the PerpetualVL2024 channel, so mixing it with a retail Office 2021 install leads to errors.
What we commonly see is a leftover trial or pre-installed Microsoft 365 copy blocking the new install. The fix is a clean removal of every older Office entry, followed by a restart, before you run the new installer.
How do you install and activate Office 2024 or Office 2021?
Retail editions are installed with Microsoft's installer and activated by entering the 25-character key, while volume-licensed LTSC editions are installed with the Office Deployment Tool and activated with a MAK or KMS, so the correct method depends on the licence type of your key rather than the version number.
Step-by-step instructions are in our Office 2024 Professional Plus install guide and the matching Office 2021 Professional Plus guide. Microsoft notes that MAK activation needs an internet connection, while KMS activation needs a KMS host on the organisation's network.
Every key we sell comes with a 30-day warranty and activation help by email at support@licencehouse.com, so if activation fails, send us the exact error code.
Frequently asked questions
Is Office 2024 better than Office 2021?
For most users, yes. Office 2024 adds new Excel functions, PowerPoint recording tools and a refreshed design, and it is supported until October 2029. Office 2021's support end date is 13 October 2026. The only clear reason to prefer Office 2021 is if you depend on Publisher, which Office 2024 does not include.
Will Office 2021 stop working after support ends?
No, Office 2021 should continue to open and save files after support ends. What stops is security updates, bug fixes and Microsoft technical support. Over time this increases risk, particularly for Outlook and for files received from unknown senders, so upgrading is the safer long-term choice for any connected PC.
Does Office 2024 include Publisher?
No. Microsoft removed Publisher from Office 2024 and Office LTSC 2024 because it is retiring the app, with support ending in October 2026. Word and PowerPoint can handle many Publisher tasks, such as flyers, calendars, labels and business cards. Existing Publisher files should be converted or exported before you remove an older Office version.
Can I open Office 2024 files in Office 2021?
Yes, both versions use the same file formats, such as .docx, .xlsx and .pptx, so files open normally. The exception is content that relies on newer features. An Excel 2024 workbook that uses the IMAGE or TEXTSPLIT functions will show errors in those cells when opened in Excel 2021.
Is Office 2024 a one-time purchase?
Yes. Office 2024, like Office 2021, is a perpetual licence bought once, with no monthly subscription. You receive security and quality updates until the end-of-support date, but no new features after release. If you need continuous new features and cloud services, Microsoft 365 is the subscription alternative.