Two decades ago, SharePoint’s Classic interface powered the first generation of digital workplaces. Today, it runs on dated page-rendering logic, ribbon-based editing, and the SharePoint Add-In app model, which Microsoft has announced it will retire in April 2026. This planned retirement, combined with ongoing security restrictions, elevates the SharePoint Classic End of Life (EOL) from a routine IT matter to a board-level strategic risk.
Gartner estimates that 70% of “application technical debt” sits inside collaboration platforms; ABB’s 2023 “Value of Reliability” survey pegs the direct cost of avoidable downtime at US$125,000 per hour on average. When Classic customizations break—especially those relying on outdated scripts or unsupported apps—businesses face immediate and measurable losses.
This guide explains every official retirement milestone, details the hidden costs of waiting, and maps a five-phase transition from SharePoint Online Classic to a modern, cloud-optimized digital workplace.
Is SharePoint Classic Really Reaching End of Life?
Yes—but primarily for SharePoint Online tenants. Microsoft has embedded multiple deadlines into its official roadmap and service communications that guarantee the phased retirement of SharePoint Add-Ins and related Classic site features:
| Date | Event | Why It Matters | Status |
| 1 Jul 2024 | Microsoft stops accepting new SharePoint Add-Ins to AppSource | No new Add-Ins can be submitted or acquired—marking a firm halt for Classic extensibility. | Completed |
| Nov 2024 | The “AllowCustomScript” setting will be deprecated and reset daily | Script Editor Web Parts (SEWP), Content Editor Web Parts (CEWP), and other Classic hacks will auto-disable every 24 hours. | Completed |
| 2 Apr 2026 | Microsoft will permanently disable SharePoint Add-In and ACS authentication | Legacy dashboards and custom apps built on Add-In model will stop working—completing the SharePoint Online Classic Experience End of Life. | Upcoming |
For on-premises farms, the timeline differs—but the direction is the same. SharePoint Server Subscription Edition (SE) continues to receive biannual feature updates, but only for Modern experiences. While Classic mode remains technically supported, it is not being actively enhanced.
Meanwhile, mainstream support for SharePoint Server 2019 ends on July 9, 2024, with extended support continuing until July 14, 2029.
Bottom line: Staying on Classic merely delays the inevitable. The technical debt grows, and support narrows—making it a matter of when, not if, you’ll need to modernize.
Why Microsoft Is Phasing Out SharePoint Classic UI?
Over the past five years, Microsoft has funneled nearly all engineering investment into the Modern SharePoint framework. This shift isn’t merely cosmetic—it reflects deep changes in how today’s users work: mobile-first, security by default, and deeply embedded within Microsoft 365.
The Classic UI simply can’t keep up with those demands or the rapid pace of Microsoft’s cloud release cycle. Here’s why the move to Modern is not only logical—it’s essential.
1. Cloud-Native Performance
Modern pages render client-side using lightweight JavaScript bundles and pull structural assets like CSS and images from Microsoft’s global CDN network. With over 60 edge locations, this dramatically reduces latency.
Independent testing shows first paint time drops from 3–4 seconds on Classic publishing pages to around 1.8 seconds on Modern sites, assuming standard 25 Mbps broadband. Add in HTTP/2 multiplexing, and total load time improves by another 15–20%.
Modern loads faster, reduces bounce rates, and improves search adoption.
2. Mobile-First Accessibility
Modern SharePoint uses responsive section grids, semantic HTML5 tags (e.g., <main>, <nav>), and ARIA landmarks that screen readers can automatically interpret.
Microsoft’s Accessibility Insights tool scores Modern pages 98+/100 against WCAG 2.1 AA guidelines out of the box. Classic pages, by contrast, often fail keyboard navigation or color contrast standards—especially older ribbon pages.
Bottom line: For U.S. federal contractors, that difference can be the line between procurement eligibility and a costly Section 508 remediation.
3. Deeper Microsoft 365 Integration
Modern SharePoint sites are group-connected. Each one is automatically tied to a Microsoft 365 Group, enabling:
- One-click surfacing in Microsoft Teams (no connectors needed)
- Branded Viva Connections cards on mobile
- Loop component support for real-time co-authoring in Outlook and Word
Classic sites lack this native integration, which fragments user experience across tools and forces duplicate permissions, context switching, and missed notifications.
4. Security & Compliance by Default
Modern SharePoint integrates directly with Microsoft Purview and supports:
- Sensitivity labels (e.g., “Confidential – Finance”) that enforce encryption
- Information Barriers to restrict communication between regulated teams
- Multi-geo data residency to meet regional compliance requirements
Classic pages do not support these features natively, often requiring brittle custom scripts or third-party add-ons that become risk factors during SOC 2 or HIPAA audits.
5. Future-Proof Development
Modern development is powered by the SharePoint Framework (SPFx)—a standards-based model aligned with Microsoft 365 and Azure AD. Developers can use React, Angular, or vanilla JavaScript to build components that work across:
- SharePoint
- Microsoft Teams
- Viva
- Outlook (via Loop)
Meanwhile, the legacy SharePoint Add-In model will stop working after April 2, 2026, when Azure Access Control Services (ACS) is retired. No new tokens will be issued, and existing Add-Ins will return authentication errors.
SPFx adopters gain future-proof tools—Graph API access, reusable components, and alignment with Microsoft’s full-stack vision.
What’s Being Deprecated or Losing Support?
As Microsoft continues to retire legacy components, several Classic SharePoint features face either hard end-of-life or silent deprecation. Below is a breakdown of what’s going away—and what it means for your business.
| Feature | Deprecation Path | Impact on Business |
| Add-Ins / Azure ACS | Hard retirement on April 2, 2026 | KPI dashboards, authentication proxies, and line-of-business widgets built on the Add-In model will stop working. No token issuance, no backward compatibility. |
| Custom Script | Global block begins November 2024 | Script Editor and Content Editor web parts will auto-disable every 24 hours. jQuery hacks and DOM manipulation will vanish—breaking page layouts and custom UX. |
| Classic Web Parts | No ongoing engineering support | Legacy parts like Content Query, Chart, and Silverlight are already read-only in many tenants. They won’t be fixed or updated moving forward. |
| InfoPath & Designer Workflows | 2013 workflow engine removed in SharePoint Online by 2026 | Any approval, provisioning, or automation flow tied to Classic lists must be rebuilt using Power Automate or Power Apps. |
| Classic Master Pages / Ribbon | Frozen codebase, no Modern migration path | Branding tied to master pages and ribbon customizations won’t carry forward. Sites must be rebuilt using Modern site theming and extensions. |
Even if a Classic page technically loads, Microsoft has stated that deprecated feature issues will not be eligible for support after retirement deadlines. That includes Add-In troubleshooting, ACS token failures, or script injection anomalies.
Why Staying on SharePoint Classic is Risky?
As Microsoft sunsets Classic SharePoint components, businesses still relying on them face a growing list of operational, security, and compliance risks. Here’s why staying on Classic isn’t just outdated—it’s potentially damaging.
1. Compliance Exposure
Modern SharePoint writes every file action, query and permission change to the Microsoft Purview Unified Audit Log (UAL). Classic pages often rely on Script-Editor or JSLink customizations that operate outside this pipeline; Microsoft explicitly warns that once you allow custom script you “can’t audit the insertion of script”.
In regulated sectors (FedRAMP, CMMC, ISO 27001), that blind spot is routinely flagged by assessors as a high-risk gap, delaying an Authority to Operate (ATO) and pushing migration ROI into the next fiscal year.
2. Security Debt
Microsoft’s Secure Future Initiative enables granular Conditional Access policies, such as restricting specific SharePoint libraries to FIDO2-authenticated users or blocking downloads on unmanaged devices. These controls apply only to Modern, group-connected sites that issue Azure AD tokens via the modern page framework.
Classic pages lack this infrastructure and cannot consume policy claims tied to user risk or device state. A compromised session token on a Classic site often results in broader access inheritance, forcing SOC teams to maintain separate playbooks and extending investigation timelines by up to 2x.
Source: https://learn.microsoft.com/en-us/entra/identity/conditional-access/overview
3. Productivity Drag
Classic libraries still depend on deep folder trees and static views. Microsoft’s own Modernization guidance shows that Modern sites add metadata filters, instant-search highlights and faster client-side rendering—key drivers of user adoption and reduced click depth.
Even a conservative 5-minute daily saving in document retrieval for a 2,000-person firm equates to ≈ US $400 k a year in recovered productivity at a $50/hour fully-loaded cost.
4. Hidden Opex
Beginning November 2024, the Allow Custom Script toggle will reset every 24 hours; admins who still need Classic scripts must re-enable them daily or schedule PowerShell workarounds.
Every cumulative SharePoint Online update also risks breaking un-supported master pages, CEWPs and jQuery hacks—costing unplanned regression-test cycles and outage windows.
5. Vendor Abandonment & Tooling Desert
Microsoft has formally scheduled a hard retirement of the SharePoint Add-In model and Azure ACS on 2 April 2026.
Most major ISVs (Nintex, K2, Layer2, etc.) are now “Modern-first,” and many Classic-only add-ins will stop receiving security patches before that date. As backup, governance and analytics vendors follow suit, organizations clinging to Classic face last-minute migrations at premium consulting rates.
Your Options: Migrating from Classic to Modern (Detailed Process)
Phase 1: Inventory & Assessment
Run the PnP Modernization Scanner to capture pages, Add-Ins, custom actions, event receivers, and inline scripts across the tenant. The built-in Excel dashboards highlight “modernization readiness” at site-collection level.
Classify findings:
- Critical – business stops if the element fails
- Important – daily productivity impact
- Long-tail – archival or seldom accessed material
In practice, large environments (~10 000 sites) show 15-20 % Critical items, giving you a clear targeting matrix (figure based on aggregated scanner projects across three global tenants).
Phase 2: Target Architecture & Branding
| Design Choice | Modern Technique | Source |
|---|---|---|
| Flat over deep navigation | Replace subsites with hub-site topology for human-readable URLs and simpler permissions. | — |
| Corporate theming | Use the JSON-based Fluent theme engine to map tokens such as themePrimary and themeLighterAlt—no more master-page hacks. |
(Microsoft Learn) |
| Group-aligned security | Connect legacy team sites to Microsoft 365 Groups (“groupify”) to unlock Teams, Planner, and Loop without extra licenses or content moves. | (Microsoft Learn) |
Phase 3: Pilot & Proof of Concept
| Pilot Metric | Classic Baseline | Modern Goal |
| First Paint (ms) | 3,400 | 1,800 |
| Mobile Accessibility Score (WCAG) | 63 / 100 | 92 / 100 |
| Time‐to‐Find Document (s) | 45 | 18 |
Pilots validate performance targets and surface edge-case blockers (e.g., deeply nested SharePoint Designer 2010/2013 workflows) before you scale. Microsoft’s own modernization guidance recommends pilot-then-wave execution to reduce risk.
Phase 4: Migration Waves
| Stream | Modernization Tooling | Key Tip | Source |
| Content migration | ShareGate Migrate – “Copy if newer (incremental)” mode | Run incremental passes after business-hours cut-over to capture late edits. | ShareGate Help |
| Page transformation | PnP PowerShell Convert-ToPnPPage for wiki/ web-part pages; publishing cmdlets for portals |
Expect manual adjustments on hero web parts and custom page layouts. | Microsoft Learn |
| Bulk publishing conversion | PnP sample scripts for classic publishing portals → Modern comms sites | Automate hundreds of pages in one run; keep author metadata with – -KeepPageCreationModificationInformation. |
Microsoft Learn |
| Custom app re-platform | Port Add-Ins to SPFx; align permission scopes to least-privilege | SPFx components render across SharePoint, Teams, Viva, and Outlook. | Microsoft Learn |
| Workflow redevelopment | Power Automate cloud flows; call Azure Functions for complex logic | Use solution-aware connectors for ALM. | — |
| Search & metadata uplift | Replace deep folders with managed metadata; auto-classify with Syntex where licensed | Improves refiners and Viva Topics discovery. | — |
A 5 TB / 1 200-site tenant tackled in two parallel threads typically completes Waves 1-4 in 18–24 weeks when transformation tasks run nightly.
Phase 5: Governance & Continuous Improvement
- Retention: publish Purview retention labels to auto-expire temporary project sites and ensure immutable records.
- Information Barriers: enforce dataset segregation (e.g., R&D vs Sales) directly in SharePoint and Teams.
- Adoption dashboards: a Power BI report pulls site-usage telemetry; sites under 30 % monthly active users trigger a coaching workflow.
- Center of Excellence: a quarterly forum curates approved SPFx patterns, Power Apps templates, and Viva Learning paths, ensuring Modern stays modern.
Putting It All Together
Following this five-phase approach turns a high-risk, one-off “lift & shift” into a governed, data-driven programme:
- Know exactly what you have before touching a single page.
- Design a Modern-native landing zone (hub sites, themes, Groups).
- Prove the gains in a pilot, then scale by wave.
- Automate repeatable tasks (PnP + ShareGate) and rebuild only what adds value.
- Institutionalize governance so Modern stays secure, compliant and adopted.
Costs, ROI, and Budget Considerations
Note: Use these numbers as an illustrative model—they combine publicly verifiable benchmarks (cited) with typical labor‐rate assumptions from real migration projects. Adjust the inputs to match your own rates, volumes, and risk posture.
| Cost Line | Classic Status Quo (Annual) | After Modern Migration (Annual / One-off) | Sources & Notes |
|---|---|---|---|
| Maintenance & Regression Testing | US $425 K (≈1 500 engineering hrs. × $283 blended rate) | US $140 K (Modern self-patching; 500 hrs. × $280) | Hour estimates are drawn from three global tenants (10 K–12 K sites) that ran PnP Page Transform + ShareGate; blended rate from Gartner 2025 IT Services Benchmarks. |
| User Productivity | 7.5 hrs. lost / employee / yr × 2 000 staff → US $750 K | Modern metadata & search recover ≈4.5 hrs. → US $450 K gain | 5 min/day time-save derived from Microsoft Modernization guidance; hourly cost = US $50 fully-loaded. |
| Security / Audit Exposure | Breach impact indeterminate; IBM reports US $4.88 M global average cost / breach in 2024(IBM) | Purview + Information Barriers remove >70 % of unauthorized-sharing vectors (risk reduction, not cash in hand) | IBM Cost of a Data Breach 2024; risk-mitigation benefit should be modelled as a probability-weighted figure for your sector. |
| One-Time Migration Spend | — | US $700 K (licenses, ShareGate seats, partner-led wave delivery) | Based on a 5 TB / 1 200-site tenant using ShareGate + PnP PowerShell and a mid-tier Microsoft partner. |
| Five-Year Net Benefit | — | ≈ US $3.0 M cumulative (285 K maintenance savings + 450 K productivity gain) × 5 years – 700 K one-time = US $2.98 M | Security-breach avoidance is upside not included in the cash figure, keeping the projection conservative. |
Where to Get Help with SharePoint Classic Migration?
| Resource | What You Get | When It Makes Sense |
|---|---|---|
| Microsoft FastTrack | Remote onboarding engineers, planning templates, and self-service tool guidance for tenants with ≥150 paid Microsoft 365 seats.
No-cost data-migration execution (including SharePoint and OneDrive content) once you reach ≥500 seats. |
You already license Microsoft 365 at scale and want Microsoft engineers to steer (and, at ≥500 seats, execute) the move without added fees. |
| GitHub PnP Community | Weekly-updated, open-source tools:
– Modernization Scanner (site & customization inventory) – Page Transformation cmdlets – Search-index reset scripts and sample pipelines |
DIY teams that prefer scripting and need granular control over site-by-site modernization. |
| Specialist Microsoft Partners | Fixed-price “Classic → Modern” programmes that bundle tooling, wave planning, SPFx re-platforming, and post-go-live adoption metrics (e.g., NGenious Solutions). | You want predictable cost/timeline and a partner accountable for business-outcome KPIs rather than just lift-and-shift effort. |
| Microsoft Learn Learning Paths | Optimize web-part performance in modern pages—practical steps to cut load time and improve Core Web Vitals.
Diagnosing SharePoint Online performance issues—built-in diagnostics, Page Diagnostics tool, and troubleshooting checklists. |
Upskilling internal admins and devs so Modern stays performant and compliant long after the migration partner exits. |
If your roadmap spans on-prem estates, refer to our deep dives: SharePoint 2019 End of Life, SharePoint 2016 End of Life, SharePoint 2013 End of Life, plus tips on SharePoint workflow, SharePoint Online vs On-Premise, and Migrate from SharePoint 2019 to SharePoint Online.
Conclusion
SharePoint Classic End of Life is not a rumor—it is a dated, documented event. Organizations that act now benefit from faster load times, mobile-ready UX, tighter security, and seamless Microsoft 365 integration.
Those that wait will scramble to rebuild broken Add-Ins, rewrite workflows, and explain outages to executives and regulators. Start with a scan, design a modern architecture, run controlled pilots, cut over in waves, and institutionalize governance. Do it once—do it right—and your digital workplace stays evergreen.
SharePoint Classic End of Life FAQs
Is SharePoint Classic going away?
Yes. Add-Ins retire 2 Apr 2026, custom script is blocked, and Classic templates are hidden. Modern SharePoint becomes the only supported UI.
How to tell if a SharePoint site is classic or modern?
Classic sites display the ribbon and fixed-width layout. Modern sites have a flat command bar, responsive design, and a “New → List” lightning icon.
What is the difference between SharePoint Classic and SharePoint Modern?
Classic uses server-rendered master pages, Add-Ins, and inline script. Modern relies on client-side SPFx, Microsoft 365 Groups, responsive design, and built-in Purview compliance.
