Breaking changes in Vaadin Flow 25

[mshabarov]

Deprecated API

• [x] https://github.com/vaadin/flow/issues/21396

New Theming system

• [ ] https://github.com/vaadin/flow/issues/21272
• [x] https://github.com/vaadin/flow/issues/21609
• [ ] https://github.com/vaadin/flow/issues/21608 ⏳
• [ ] https://github.com/vaadin/flow/issues/21607
• [ ] https://github.com/vaadin/flow/issues/21606 ⏳
• [ ] https://github.com/vaadin/flow/issues/21605 ⏳

Frontend

• [ ] https://github.com/vaadin/flow/pull/21523 ⏳

Polymer -> Lit

• [ ] https://github.com/vaadin/flow/issues/21421

Binder

• [ ] https://github.com/vaadin/flow/pull/18540
• [ ] https://github.com/vaadin/flow/pull/18121 / https://github.com/vaadin/flow/issues/18120
• [ ] https://vaadin.slack.com/archives/C6RAXJATF/p1729494025391779

Dependencies

• [ ] https://github.com/vaadin/flow/pull/21466 ⏳
• [ ] https://github.com/vaadin/flow/issues/21675

Other

• [ ] https://github.com/vaadin/flow/pull/18319
• [ ] https://github.com/vaadin/flow/issues/17624
• [ ] Change annotation based view protection defaults for layouts: Now: AtLayout requires annotation, layout= does not need; V25: Both need annotations or neither need. Issue TBC
• [ ] https://github.com/vaadin/flow/issues/17617#issuecomment-1740864093 / https://github.com/vaadin/flow/pull/17745#issuecomment-1749116588
• [ ] https://github.com/vaadin/flow/issues/18153
• [ ] One bootstrapping request by default; Now: eagerServerLoad = false; V25: eagerServerLoad = true, https://github.com/vaadin/flow/issues/17602