Forum Discussion
Upgrade the framework from 3.5 to 4.8 and SharePoint 2010 to SharePoint 2019.
I’m working with one of my clients wherein they are having a few code still written on .net framework 3.5. client. wishes to upgrade the framework to 4.8 and SharePoint 2010 to SharePoint 2019.
I’m looking for some pointers to migrate an Code from 3.5 to 4.8, what could be the runtime changes/retargeting changes/breaking changes. It would be of great help if someone could give me a roadmap to address the problem – where to start from, what details to look into etc. I searched a lot and could not get any specific pointer for my use case. Please help.
Thanks in advance!
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1. Pre-upgrade preparation
System Requirements Verification
Hardware:
64-bit CPU, ≥12GB RAM (16GB+ recommended)
Storage: ≥80GB system disk space + additional database space
Software:
Windows Server 2016/2019
SQL Server 2016/2017/2019
NET Framework 4.8
Backup of critical data
Content database:
powershell
Backup-SPSite -Identity <SiteURL> -Path C:\Backup\site.bak
Customized solution: Manually backup WSP packages and code
2. Phased Upgrade Procedure
Phase 1: Migrate to an intermediate version (SharePoint 2013/2016)
Create a new SharePoint 2013/2016 farm
Upgrade using Database Append:
powershell
Mount-SPContentDatabase -Name <DBName> -WebApplication <TargetWebApp>
Test for functional compatibility
Phase 2: Upgrading to SharePoint 2019
Install SharePoint 2019 Prerequisites:
powershell
Install-WindowsFeature NET-Framework-Features, Web-Server, WAS
Attach Content Database (same as step 1)
Stage 3: Migrate .NET Framework 3.5 → 4.8
Update custom code:
Recompile solution (target framework changed to 4.8)
Replace deprecated APIs (e.g. Microsoft.SharePoint.WebPartPages)
Modify web.config:
xml
<compilation targetFramework=“4.8” />
<httpRuntime targetFramework=“4.8” />
Run HTML
3. Key Notes
Compatibility issues:
2010 workflows (SPD workflows) need to be migrated to Power Automate or Azure Logic Apps.
InfoPath forms need to be replaced with Power Apps.
Authentication Updates:
Classic Mode authentication needs to be migrated to Statement Based Authentication.
Search Architecture:
2010 search configuration needs to be rebuilt in 2019
4. Validation and Optimization
Functional Test List:
List of functional tests.
Customization of web parts and page layouts
User rights inheritance
Performance Optimization:
Enable Blob caching:
xml
<BlobCache location=“C:\BlobCache” path="\. (gif|jpg|png)$“ maxSize=”10“ enabled=”true” />
Running HTML
Configuring the Distributed Cache Service
