Skip to content

Upgrade to Umbraco 17.5.3 LTS and all dependencies #327

Description

@deanleigh

Bring UmBootstrap from Umbraco 17.2.2 to 17.5.3, with every dependency moved to its latest 17-compatible release.

Full plan with per-sprint checkboxes: planning/UMBRACO_17_LTS_UPGRADE.md

Staying on 17 LTS, not 18

The literal latest Umbraco is 18.0.2. We are deliberately staying on the LTS line.

Every community package now publishes two lines, one per Umbraco major, and the higher version number is always the Umbraco 18 one. Taking "latest" on any of them silently moves the project off LTS.

Package 17-compatible (target) 18 line (avoid)
BlockPreview 5.5.0 6.1.0
Contentment 6.2.1 7.0.1
UmbNav 4.1.8 5.0.0
uSync 17.3.6 18.0.2
uSync.Complete 17.3.11 18.0.2
Umbraco.AI 17.1.1 18.1.1
Umbraco.AI.Anthropic 17.0.0 18.0.0
Umbraco.AI.Prompt 17.1.0 18.1.0

Sprints

  • 1 — CMS core. Umbraco.Cms 17.2.2 → 17.5.3, remove the MimeKit pin
  • 2 — AI packages. To the 17.x line. Blocked on sprint 1
  • 3 — Community packages. BlockPreview, Contentment, UmbNav
  • 4 — uSync. Report before import, review serialisation churn separately
  • 5 — Documentation. In the docs worktree, includes updating the version table
  • 6 — Verification and close

Ordering is forced

Umbraco.AI 17.x hard-requires Umbraco.Cms.Core >= 17.4.0, so the CMS must move first or the restore fails.

The MimeKit pin can be removed

The pin exists because MimeKit 4.14.0 carried CVE-2026-30227, fixed in 4.15.1. MimeKit is pulled transitively via MailKit:

MailKit resolves MimeKit
Umbraco 17.2.2 4.14.1 4.14.0 (vulnerable)
Umbraco 17.5.3 4.16.0 4.16.0 (fixed)

17.5.3 resolves above the fix on its own, so the manual pin and its TODO become dead weight.

Dependabot PRs are both wrong

Close both rather than merging.

Risks

  • Contentment is the highest risk despite the smallest bump. FeatureBlockDataSource depends on IContentmentDataSource and on reading the document GUID from the API POST body via EnableBuffering() in Program.cs. Custom integration, undocumented upstream.
  • Database migrations cannot be reverted by git. Umbraco and Umbraco.AI both migrate on first boot. Database backed up before starting.

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions