Lack of replacement for strategies removed in version 10

[marcindabrowski]

Describe the bug

In version 10.0.0 a lot of strategies classes from io.getunleash.strategy package have been removed.
v10_MIGRATION_GUIDE do not mention it, and actually Readme still references to it in Activation strategies, ie: GradualRolloutRandomStrategy and all others.

Please provide clear info how it can be replaced, and fix migration guide and readme.

Steps to reproduce the bug

No response

Expected behavior

Clear migration guide.

Logs, error output, etc.

No response

Screenshots

No response

Additional context

No response

Unleash version

No response

Subscription type

None

Hosting type

None

SDK information (language and version)

Java, 10.0.0 and newer

[gastonfournier]

Thanks for reporting this, and you’re right that the docs are currently misleading here.

In v10, the built-in strategy implementations (like GradualRollout*) were moved into the Yggdrasil engine and are no longer part of the Java SDK public API. So there isn’t a 1:1 replacement class to import from io.getunleash.strategy for those built-ins.

The intended public extension point is still to provide your own Strategy implementation (and/or a fallbackStrategy) when creating DefaultUnleash.

We’ll update README.md (especially the Activation strategies section) to make this clearer and remove the misleading references to those old strategy classes.

[gastonfournier]

Quick follow-up on version guidance:

We recommend migrating to v12.

Important context: the latest v10 and v12 are effectively on the same implementation path.
So for most users, moving from latest v10 to v12 should be a low-friction upgrade, not a "large rewrite" type of major migration.

Why v12 then:

• v12 is the line that represents the intended path forward.
• It was released to make that path explicit after v11 had already been published.
• Ongoing improvements and normal forward updates should be expected on v12.

Practical guidance:

• If you need minimal immediate change, use the latest patch on your current major.
• For ongoing development, align on v12.

We also updated migration docs accordingly:

• v10_MIGRATION_GUIDE.md
• v11_MIGRATION_GUIDE.md
• v12_MIGRATION_GUIDE.md