Technical Debt decreased after migration

We just migrate from SQ-4.2 to the last LTS 4.5.6. And we noticed a strange behaviour:

• On 4.5.6 de technical debt cost get drastically reduced, while the number of issues get increased (please see attached)enter image description here

We didn't find any answer to this behaviour (change in formulas? in each violation remediation cost?)

Before migration (on 4.2): sonar-java-plugin-2.5.jar After (on 4.5.6): sonar-java-plugin-3.9.jar

Thank you in advance for any clarification, Issam

The 3.0 version included a wide-ranging reassessment of technical debt values. We had realized that many were much higher than they ought to be, so this was addressed in SONARJAVA-873.

For instance S1192 went from 10 minutes to 2 minutes.

That's why you can have more issues but less time after this upgrade.