Can I use Microsoft 365 and Office 2021 together in the same organization?

Yes, many organizations use a mixed approach. Power users run Microsoft 365, while kiosk workstations use Office 2021 perpetual licenses. Office 2021 users cannot access cloud services like Teams or SharePoint Online without separate licenses.

What happens to my data if I cancel Microsoft 365?

After cancellation, Microsoft provides a 90-day retention period during which your data remains accessible. After 90 days, data is permanently deleted. During the grace period, you can export all emails, OneDrive files, SharePoint content, and Teams conversations.

Is Office 2024 a better option than Office 2021?

Office 2024 replaces Office 2021 as the current perpetual license option and includes more recent features with a longer support lifecycle. However, the same limitations apply -- no cloud services, no Copilot, and no continuous updates.

Does Microsoft 365 E3 include everything most enterprises need?

E3 covers 80-90% of enterprise needs including full Office apps, Exchange Online, SharePoint, Teams, and basic security. Organizations needing Power BI Pro, advanced security (Defender for Endpoint), or Phone System should evaluate E5 or add-on licenses.

How do I migrate from Office 2021 to Microsoft 365?

The migration involves provisioning Microsoft 365 licenses, deploying Office apps via Microsoft 365 Apps for enterprise using Intune or Configuration Manager, migrating email to Exchange Online, and configuring OneDrive. EPC Group typically completes this in 4-8 weeks for 500-5,000 users.

Microsoft 365 vs Office 2021

Key Facts

Office 2021 reaches end of mainstream support in October 2026. After that, security patches only through 2026.

Microsoft 365 includes cloud services — Exchange Online, SharePoint, OneDrive, and Teams — that Office 2021 does not.

Microsoft 365 Copilot ($30/user/month add-on) requires a Microsoft 365 base license. Copilot does not work with Office 2021.

For enterprises planning AI deployment, Microsoft 365 E3 or E5 is the only viable path.

Microsoft 365 vs Office 2021: How to Choose

Microsoft 365 is a subscription that gives you continuously updated Office apps, cloud storage, Teams, Exchange Online, and enterprise security. Office 2021 is a one-time purchase of desktop apps frozen at the 2021 feature set. For enterprises, Microsoft 365 is almost always the right choice — here is why.

Key differences at a glance

Category	Microsoft 365	Office 2021
Licensing model	Subscription (per user/month)	One-time purchase
Apps included	Word, Excel, PowerPoint, Outlook, Teams, OneNote, Access	Word, Excel, PowerPoint, Outlook, OneNote (no Teams)
Updates	Continuous feature updates via Current Channel	Security updates only (no new features)
Cloud services	Exchange Online, SharePoint, OneDrive, Teams	None (desktop apps only)
AI features	Copilot add-on available ($30/user/month)	No AI or Copilot features
Security	Defender, Purview, Conditional Access, DLP	No enterprise security features
Support lifecycle	Ongoing (tied to subscription)	End of support: October 2026
Enterprise pricing	E3: $36/user/month · E5: $57/user/month	~$440/user one-time (LTSC 2021)

Key facts

Office 2021 reaches end of mainstream support in October 2026. After that, security patches only through 2026.
Microsoft 365 includes cloud services — Exchange Online, SharePoint, OneDrive, and Teams — that Office 2021 does not.
Microsoft 365 Copilot ($30/user/month add-on) requires a Microsoft 365 base license. Copilot does not work with Office 2021.
For enterprises planning AI deployment, Microsoft 365 E3 or E5 is the only viable path.

Microsoft 365 enterprise plans

Microsoft 365 Apps for Enterprise ($12/user/month) — Office apps only, no Exchange or Teams included.
Microsoft 365 E3 ($36/user/month) — full suite: apps, Exchange Online, SharePoint, Teams, Intune, basic compliance.
Microsoft 365 E5 ($57/user/month) — adds Defender for Endpoint P2, Purview Insider Risk, advanced compliance, Power BI Pro.

When Office 2021 still makes sense

Office 2021 (LTSC) fits a narrow set of scenarios.

Disconnected or air-gapped environments that cannot use cloud services.
Regulated systems where software version control is mandatory and continuous updates are not permitted.
Specialized devices (kiosks, factory floor terminals) where desktop apps are needed with no cloud connectivity.

For most enterprise users, these scenarios do not apply. If your users need email, Teams, or AI features — choose Microsoft 365.

Migrating from Office 2021 to Microsoft 365

The migration has four steps. EPC Group runs each step with minimal user disruption.

Provision Microsoft 365 licenses for all users.
Deploy Microsoft 365 Apps for Enterprise via Intune or Configuration Manager.
Migrate email to Exchange Online (if not already there).
Configure OneDrive for Business file synchronization and redirect My Documents.

Timeline: small organizations (under 500 users) typically migrate in 4–8 weeks. Enterprise migrations take 8–16 weeks with phased rollout.

Impact on security and compliance

Microsoft 365 is not just a productivity upgrade. For enterprises, it changes your security and compliance posture significantly.

Exchange Online adds anti-phishing, Safe Attachments, and Safe Links — not available in on-premises Exchange or Office 2021.
Microsoft Purview DLP, sensitivity labels, and eDiscovery require Microsoft 365 licensing.
Conditional Access policies in Entra ID require Microsoft 365 apps on Current Channel — not Office 2021.
HIPAA, SOC 2, FedRAMP, and CMMC compliance frameworks all assume Microsoft 365, not Office 2021.

Frequently asked questions

What is the main difference between Microsoft 365 and Office 2021?

Microsoft 365 is a subscription with continuously updated apps plus cloud services (Exchange Online, SharePoint, OneDrive, Teams). Office 2021 is a one-time purchase of desktop apps with no cloud services and no feature updates after release. Office 2021 reaches end of support in October 2026.

Can I use Microsoft Copilot with Office 2021?

No. Copilot for Microsoft 365 requires an active Microsoft 365 subscription (E3, E5, Business Standard, or Business Premium) plus the $30/user/month Copilot add-on. Office 2021 does not qualify and has no AI features.

Is Microsoft 365 more expensive than Office 2021?

Microsoft 365 E3 is $36/user/month ($432/year). Office 2021 LTSC is approximately $440 per device one-time. Over three years, M365 E3 costs ~$1,296 per user — but includes cloud services, security, and continuous updates that Office 2021 does not provide.

What happens when Office 2021 reaches end of support?

Office 2021 mainstream support ends October 2026. After that, Microsoft provides security patches only through the extended support date. No new features will be added. Organizations still on Office 2021 after 2026 face increasing security risk as vulnerabilities are discovered but not fully patched.

How long does migrating from Office 2021 to Microsoft 365 take?

Four to eight weeks for most organizations under 500 users. Enterprise migrations (1,000+ users) with email migration, SharePoint setup, and phased rollout take 8–16 weeks. EPC Group uses Intune or Configuration Manager to deploy Microsoft 365 Apps for Enterprise at scale.

Upgrade to Microsoft 365

EPC Group manages Microsoft 365 migrations for enterprises of all sizes. Call (888) 381-9725 or schedule a discovery call to plan your migration.

Microsoft 365 Strategy: 2026 Considerations for Microsoft 365 Vs Office 2021 How To Choose The Right Product

Microsoft 365 E5 vs E3 in 2026 is fundamentally a security and compliance decision. E5 ($57/user/mo) bundles Microsoft Defender for Endpoint Plan 2, Microsoft Defender for Cloud Apps, Insider Risk Management, Communication Compliance, Microsoft Sentinel-fed audit logs, Customer Lockbox, and Audit (Premium) 6-year retention; the full set is roughly $35/user/mo of additional value if purchased as E3 plus add-ons. For regulated industries, the E5 bundle is typically less expensive than the equivalent E3 stack.

Microsoft 365 GCC High vs Commercial tenant in 2026 governs whether a contractor can hold Controlled Unclassified Information (CUI) for federal work under CMMC Level 2 (110 NIST 800-171 controls) or Level 3 (134 controls). GCC High costs roughly 2x the commercial equivalent (Microsoft list price $23-$57/user/mo) but is non-negotiable for any DoD prime or sub-prime handling CUI. Migration from Commercial to GCC High is a 14-22 week project.

Decision factors EPC Group evaluates

Customer Lockbox + Audit (Premium) configuration for regulated tenants

Microsoft Purview Compliance Manager assessment baseline (HIPAA, SOC 2, GDPR, NIST AI RMF)

E5 vs E3 + add-ons total-cost analysis at organization scale

Microsoft Defender for Endpoint Plan 2 deployment versus Plan 1 + add-ons

GCC High vs Commercial tenant decision for federal contractors

See related EPC Group services at /services or schedule a discovery call at /contact.

Microsoft 365 vs Office 2021: How To Choose The Right Product