SharePoint Modernization — From Classic to Modern Experience

SharePoint Modernization: Classic to Modern Migration Guide (2026)

SharePoint Modernization is the migration from SharePoint Classic (2007/2010/2013/2016/2019/Online classic) to SharePoint Online Modern. This is the working enterprise playbook EPC Group uses for Fortune 500 SharePoint migrations — assessment, content cleanup, modern site provisioning, hub site architecture, Microsoft Viva integration, and Microsoft 365 Copilot enablement.

EPC Group has delivered SharePoint migrations and modernizations for Fortune 500 organizations since SharePoint 2003. We've delivered over 1,500+ SharePoint engagements across healthcare, financial services, government, manufacturing, and technology.

TL;DR — 6-Phase Modernization

Phase	Duration	Output
1. Discovery and assessment	Weeks 1-3	Tenant inventory, content audit, modernization scope
2. Content cleanup and labeling	Weeks 3-8	60-70% volume reduction typical, sensitivity labels applied
3. Modern architecture design	Weeks 6-10	Hub-and-spoke topology, governance model
4. Migration (waves)	Months 3-9	Phased migration, no business disruption
5. Modern enablement	Months 6-12	Microsoft Viva, Copilot, Power Platform integration
6. Adoption and governance	Ongoing	Adoption telemetry, content lifecycle automation

Mid-market: 6-9 months. Fortune 500: 12-24 months.

Phase 1: Discovery and Assessment

Tenant Inventory

Asset	What to Capture
Site collections	Count, size, last modified, owner
Subsites	Depth, dependency on parent, modernization candidate
Lists and libraries	Item count, size, schema complexity
Customizations	Solutions, web parts, workflows, custom code
InfoPath forms	Count and complexity (deprecated, must replace)
Workflows	SharePoint Designer, Nintex, K2
Content types	Custom vs OOTB
Sensitivity labels	Current coverage
External sharing	Sites with external users, anonymous links

Microsoft 365 Apps Compatibility

• SharePoint Designer 2013 (deprecated but functional for migration analysis)
• Microsoft 365 Tenant Migration Tool (SPMT)
• ShareGate, AvePoint, Quest tools (commercial)
• PnP PowerShell (open-source)

Modernization Decision Tree

For each site, decide:

• Lift-and-shift — migrate as-is to Modern (minimal customization)
• Modernize in place — apply Modern templates, refactor minor customizations
• Rebuild on Modern — heavy customization, build fresh on Modern
• Retire — content no longer needed, archive and delete
• Consolidate — merge into existing Modern site

Typical Fortune 500 distribution: 40% lift-and-shift, 25% modernize, 15% rebuild, 15% retire, 5% consolidate.

Phase 2: Content Cleanup

Why Cleanup First

• 60-70% of legacy SharePoint content is duplicate, obsolete, or trivial (DOT data)
• Migration time scales with content volume
• Microsoft 365 Copilot grounding quality scales inversely with junk content
• Storage costs and operational complexity reduce dramatically

Cleanup Sequence

1. Inventory and classification — Microsoft Purview Data Lifecycle Management scan
2. Duplicate detection — fingerprint-based duplicate identification
3. Stale content identification — last-accessed date older than 5 years
4. Owner outreach — automated emails to content owners for review
5. Archive declared records — move to Microsoft Purview Records Management
6. Delete candidates — retention policy disposition workflow

Sensitivity Labeling Backfill

Apply Microsoft Purview sensitivity labels during cleanup:

• Public, General, Confidential, Highly Confidential, Restricted
• Industry-specific Restricted sub-labels (PHI, MNPI, CUI)
• Auto-labeling rules for regex/dictionary matches
• Coverage target: 80%+ on regulated content within Phase 2

Phase 3: Modern Architecture Design

Hub-and-Spoke Topology

Modern SharePoint architecture is flat and hub-organized:

Tenant
├── Intranet Hub (corporate communication)
│   ├── HR Site
│   ├── Finance Site
│   ├── IT Site
│   └── Legal Site
├── Department Hubs
│   ├── Sales Hub
│   │   ├── Region 1 Site
│   │   ├── Region 2 Site
│   │   └── Sales Operations Site
│   └── Engineering Hub
│       ├── Product A Site
│       ├── Product B Site
│       └── Engineering Operations Site
└── Project Sites (orphan or department-aligned)

Site Templates

EPC Group standard Modern templates:

• Communication Site — broadcast/landing pages (HR, IT, Marketing)
• Team Site — collaborative workspaces (project, department)
• Hub Site — navigation and visual unifier across associated sites
• Microsoft 365 Group-connected Team Site — anchored to a Microsoft 365 Group with mailbox, Planner, Teams

Governance Model

• Site provisioning workflow — request → approval → automated provisioning
• Naming conventions — predictable, searchable
• Owner accountability — every site has a primary and secondary owner
• Lifecycle policies — inactive site detection, owner re-attestation, archive/delete
• Sharing policies — internal default, external by exception with sensitivity-label-aware controls

Phase 4: Migration Waves

Wave Structure

EPC Group standard wave structure:

• Wave 0 (Pilot) — 5-10 sites, small department, validate process
• Wave 1 (Early Adopter) — 50-100 sites, 1-2 department, refine process
• Wave 2 (Department) — 200-400 sites, full department, scale validation
• Wave 3+ (Enterprise) — Department-aligned waves, 200-500 sites per wave
• Wave Final (Cleanup) — orphan sites, edge cases, retire-candidates

Migration Tooling

• SharePoint Migration Tool (SPMT) — Microsoft free, supports SharePoint 2013+ and file shares
• Microsoft 365 Migration — first-party, recommended for cloud-to-cloud (tenant-to-tenant)
• ShareGate — commercial, deeper customization handling, schema mapping
• AvePoint Cloud Migration — enterprise-scale, regulatory-industry focus
• Quest Migration Manager — enterprise-scale, hybrid environments

Cutover Planning

• Read-only freeze on source 24 hours before cutover
• Delta migration for changes during freeze window
• DNS/redirect cutover for branded URLs
• User communication 7/3/1 days before cutover
• Post-cutover hyper-care window (2 weeks)

Phase 5: Modern Enablement

Microsoft Viva Integration

• Viva Connections — corporate intranet feed surfaced in Microsoft Teams
• Viva Engage (Yammer) — community and conversation
• Viva Topics — AI-generated knowledge graph from SharePoint content
• Viva Learning — corporate learning content surfaced in Teams
• Viva Insights — productivity and wellbeing analytics
• Viva Goals — OKR management integrated with Teams

Microsoft 365 Copilot Enablement

Modern SharePoint architecture is the foundation for Microsoft 365 Copilot quality:

• Sensitivity labels enable Restricted-tier blocking
• Hub-and-spoke topology improves grounding scope
• Cleaned content reduces grounding hallucination risk
• Microsoft Purview audit captures Copilot prompt history
• SharePoint Restricted Search controls grounding boundaries

Power Platform Integration

• Replace InfoPath forms with Power Apps
• Replace SharePoint Designer workflows with Power Automate
• Build custom apps integrated with SharePoint lists
• Build Copilot Studio agents grounded on curated SharePoint libraries

Phase 6: Adoption and Governance

Adoption Telemetry

Microsoft 365 admin center adoption analytics + Microsoft Viva Insights track:

• Active user rate by department
• Site usage patterns
• Modern feature adoption (vs classic patterns)
• External sharing patterns
• Microsoft 365 Copilot adoption per user

Content Lifecycle Automation

• Microsoft Syntex auto-classification on upload
• Microsoft Purview retention labels auto-applied
• Microsoft Purview Records Management for declared records
• Inactive site alerts with owner re-attestation
• Disposition review workflow before deletion

Frequently Asked Questions

How much does SharePoint modernization cost?

EPC Group fixed-fee SharePoint Modernization:

• Mid-market (50-200 site collections): $250K-$500K
• Enterprise (200-1000 site collections): $500K-$1.5M
• Fortune 500 (1000+ site collections): $1.5M-$5M

Includes assessment, planning, content cleanup, migration, modern enablement, and 90-day adoption support.

How long does it take?

• Mid-market: 6-9 months
• Enterprise: 12-18 months
• Fortune 500: 18-30 months

Faster is technically possible but creates content quality, governance, and Copilot grounding risk.

Do we need to migrate?

For SharePoint 2013/2016/2019 on-premises: yes, before end-of-support dates. For SharePoint Online Classic: yes, to enable Microsoft 365 Copilot, Viva, and Power Platform integration. Classic surfaces are increasingly limited and will continue to deprecate.

What if we have heavy InfoPath / Designer customizations?

EPC Group standard pattern: Power Apps for forms, Power Automate for workflows. The decision matrix considers complexity, business criticality, and team skills. Some customizations are best replaced rather than migrated.

What about Microsoft 365 Copilot?

Modern SharePoint is the foundation for Microsoft 365 Copilot quality. Classic SharePoint surfaces are increasingly excluded from Copilot grounding. Modernization is typically a prerequisite for Copilot rollout.

Who delivers SharePoint engagements?

EPC Group senior architects with combined SharePoint experience since 2003. Errin O'Connor is a 4-time Microsoft Press author including a SharePoint book. Senior architects bring MCSE: Productivity, MS-301 Deploying SharePoint Server Hybrid, and Microsoft Information Protection Specialist credentials.

Next Steps

Schedule a 30-minute SharePoint modernization discovery call at /schedule or call (888) 381-9725. Senior architects (not sales) take discovery calls.

Related reading: SharePoint Online Migration Guide, SharePoint Permissions Best Practices Enterprise Guide, SharePoint Document Library Best Practices, Microsoft Purview Data Governance Enterprise Guide, and Copilot for Microsoft 365 Complete Deployment Guide.