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It's always ideal to have the same version of Jira running on both source and target instances. However, with the latest version of Configuration Manager for Jira app, one can have two different Jira versions on the source and target instances provided the version of Configuration Manager for Jira app is identical.
Example: Configuration Manager for Jira v6.6.8 is supported for Jira versions between 7.8.0 to 8.11.0. In the 6.6.8 version of CMJ, any version of Jira can be installed between v7.8.0 to v8.11.0 in the source and target, but the CMJ app version should be identical to v6.6.8 at both places.
An important point to remember: If the Jira versions are different, the target instance shouldn't be running on an older version than the source instance.
Example: Jira source instance is on v7.8.0 and the target is on v8.10.0. Then CMJ Works perfectly. However, if the Jira source instance is on v8.10.0 and the target is on v7.9.0, the CMJ might not give accurate results.
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If the Jira versions are close they don't differ in any major features and so it is absolutely safe to use CMJ to create and deploy 100% valid and full snapshots. Also, you don't need to use the same version of CMJ, but it is recommended to use close versions of the CMJ if the same versions are not possible, so you could get the same set of features and object support.
Example: Jira source instance is on v7.8.0 and the target is on 7.9.0. CMJ is absolutely safe to create and deploy valid and full snapshots.
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