Upgrade Episerver CMS without buying a different product

Episerver rebranded as Optimizely on 27 January 2021. Same vendor line. CMS 11 is off routine patches. 11 to 12 is Framework to Core. We will tell you whether to climb, stop at 12, or leave.

Book a free 30-minute discovery callTalk through your Optimizely site

Australian .NET team. We look at the site before anyone talks about a rebuild.

Still running Episerver or Optimizely CMS 11?

The site still works. That is why it has been left alone.

If the repo still says EPiServer, you are on the same CMS line that is now called Optimizely. A lot of the installs we hear about were built on CMS 11, with Find, Forms, and a handful of Geta packages. Then the person who understood the Alloy-era templates left.

You might recognise one of these:

  • The backoffice URL is still /EPiServer
  • You are on CMS 11, and someone said “just go to 13”
  • Web Forms templates or an old Alloy site are the front end
  • Find / Search and Navigation is load-bearing
  • A DXP hostname migration is sitting in the portal unread
  • You are not sure whether to stay on Optimizely or leave it

You do not need a new brand, or a DXP pitch. You need a clear read on the solution you already have.

Why these sites stall

Optimizely CMS is still a real product. Current major is CMS 13, on .NET 10. From 10 April 2026, all new product development is on the latest major. Severe bugs and security are actively monitored for the current major and one prior — today CMS 13 and CMS 12. CMS 11 and earlier are not in that pair.

CMS 11 off patches

Framework to Core

Two majors

Find gone

CMS 11 is off routine monitoring. It is not a forced EOL.

The 10 April 2026 policy: no ongoing bug or security monitoring or patch releases for CMS 11 and earlier, except severe security vulnerabilities raised by customers or partners. Support teams will still investigate; resolution may vary. Optimizely does not disable environments. “No formal EOL” is not the same as “still patched”. CMS 12 is still receiving 2026 patches. It is the maintained prior major, not a 2028 home.

Caption under the diagram:

11 to 12 is a Core port. 12 to 13 is a second major. You cannot skip 12.

11 to 12 is a Framework to ASP.NET Core port of your solution.

Vendor docs: CMS 12 does not require a data migration; finish the migration within a year of starting. Three phases — Microsoft Upgrade Assistant plus the Optimizely extension, fix remaining code, and DXP customers migrate the service environment in the PaaS portal. After the last 11 environment go-live, the CMS 11 env is kept 14 days, extendable. Web Forms will not come across. This is not a NuGet bump.

You cannot go 11 to 13 directly.

Official CMS 13 docs (updated 18 August 2026): you must already be on CMS 12. Target net10.0, update every EPiServer. / Optimizely. package, and fix breaking APIs — SiteDefinition to the Application model, PageReference to ContentReference, ContentArea.FilteredItems removed. Previous migration tools are deprecated. The CMS 13 database migration on first startup is irreversible. A CMS 12 app cannot run against a CMS 13 database. Backup is the only rollback.

Find is removed. Add-ons are the hard part.

Search and Navigation (EPiServer.Find) is not supported on 13. Dynamic Properties, Mirroring, and Plugin Manager are gone. Admin moves off /EPiServer — bookmarks, health checks, and hardcoded links break. Graph and Opti ID are mandatory for the full CMS 13 brochure. Vendor calls third-party package incompatibility the single largest area of effort. Forms, Commerce, Geta, and Language Manager each have their own major.

None of that makes the content or the information architecture worthless. It does mean “upgrade 11 to 13 over a weekend” is the wrong first move.

How we work

We start with the install, not with a destination.

1

Look at what you have

CMS major, Framework versus Core, Web Forms versus MVC, Find / Forms / Commerce / Geta packages, DXP versus self-hosted, and whether anyone has already started the Upgrade Assistant. We will tell you whether this is one major or two.

2

Decide the job

There are three honest outcomes. We recommend one, not all three.

3

Do the work in stages

Content and the pages people actually use come across. Web Forms templates, Find indexes, and add-ons that have no 12 or 13 equivalent do not. The 13 database cutover is planned as one-way.

4

Hand it back so the next person can run it

Source, a short record of what changed, and a site someone else can understand.

Three honest outcomes

  • Land on CMS 12 if you are on 11 and cannot absorb Graph and .NET 10 this year. It is the maintained prior major — severe bugs and security only, no new product development. Not a 2028 home.
  • Climb to CMS 13 on .NET 10 once you already have a CMS 12 solution. That is the current major. PaaS or SaaS flavour is a discovery question, not a converter.
  • Leave Optimizely for another CMS, Optimizely SaaS CMS as a different product surface, or custom ASP.NET Core if the customisations are the whole job.

We will not tell you Episerver was discontinued. We will not tell you WordPress is the answer to every CMS 11 site. If you already know you want to stay on Optimizely forever, an Optimizely-only partner may be a better fit. If you want an honest fork in the road, talk to us.

What we need for the first call

A URL and a rough version is enough to start.

  • Which CMS major: 11 or earlier (often still branded Episerver), 12, or already 13
  • Whether the front end is Web Forms, MVC, or already Core
  • Which add-ons are load-bearing: Find, Forms, Commerce, Geta, Language Manager
  • DXP / PaaS or self-hosted, and whether a portal migration has started
  • Hosting today (old Windows server, Optimizely DXP, someone else’s box)
  • What “done” looks like: stop at 12, go to 13, leave Optimizely, or get a clear picture first

The first call is 30 minutes. You leave with a recommendation you can take to a manager, not a rebuild estimate pulled from thin air.

Related work

We have taken over and modernised ageing .NET systems for Australian organisations, including work with Data#3, Hastie, NESS, and NSW Health. That is related Microsoft web work, not a published Optimizely or Episerver case study. We do not hold an Optimizely partner badge. A CMS 11 or 12 site still starts with its own assessment. We will not pretend it is a project we have already published.

FAQ

Was Episerver discontinued?
No. Episerver reintroduced itself as Optimizely on 27 January 2021. An Episerver CMS 11 owner is on Optimizely CMS 11. Same vendor line, new name.
Is CMS 11 end-of-life on a date?
Optimizely does not enforce a forced EOL or disable environments. From 10 April 2026, CMS 11 is off routine bug and security monitoring. That is already the policy, with or without a kill date.
Can we go 11 to 13 in one upgrade?
No. Official CMS 13 docs require a CMS 12 solution first. 11 to 12 is the Framework to Core port. 12 to 13 is .NET 10, Graph, and a one-way database migration.
Does Find work on CMS 13?
No. Search and Navigation is not supported. You implement Optimizely Graph or a third-party search. The 13 database migration cannot be rolled back in place.
We only have a backup and an old server.
That is common. Bring that.

Talk through the Optimizely site you already have

Thirty minutes. Bring a URL and a version number if you know it. We will tell you whether to stop at 12, climb to 13, or leave — and we will not treat Episerver as a different product.

Book a free 30-minute discovery call