We are upgrading from 7.10 to 7.17. using camunda rest and webapp with our application. Post changes to use 7.17 the application fails to start with following error
Caused by: java.lang.IllegalStateException: Task already scheduled or cancelled
at java.base/java.util.Timer.sched(Timer.java:402)
at java.base/java.util.Timer.scheduleAtFixedRate(Timer.java:329)
at org.camunda.bpm.engine.impl.metrics.reporter.DbMetricsReporter.start(DbMetricsReporter.java:59)
at org.camunda.bpm.engine.impl.ProcessEngineImpl.(ProcessEngineImpl.java:141)
at org.camunda.bpm.engine.impl.cfg.ProcessEngineConfigurationImpl.buildProcessEngine(ProcessEngineConfigurationImpl.java:1017)
at org.camunda.bpm.engine.spring.SpringTransactionsProcessEngineConfiguration.buildProcessEngine(SpringTransactionsProcessEngineConfiguration.java:67)
at org.camunda.bpm.engine.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:55)
at org.camunda.bpm.engine.spring.ProcessEngineFactoryBean.getObject(ProcessEngineFactoryBean.java:34)
at org.springframework.beans.factory.support.FactoryBeanRegistrySupport.doGetObjectFromFactoryBean(FactoryBeanRegistrySupport.java:169)
… 29 common frames omitted
Hey @aprasad and welcome to the Camunda Community! 
While updating from 7.10 to 7.17 have you followed our documentation?
Right here you can find all the steps you need to take care about when updating the version:
Sometime the database schema changes or some API endpoints might change. Due to this it is sometimes quite important to check on this. Especially when updating that many versions. 
Let me know if this information can solve your problem!
-Thomas