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When JEMHC processes an email, the emails message-ID is stored. If a subsequent email refers to the original message-ID in its In-Reply-To and References headers and if enabled sub option(s) are enabled i.e.In-Reply-To and References; then JEMHC will drive threading dependent on the related header(s) options are enabled then issue association will occur. Email Threading behaviour can be disabled or modified via Profile > Project Mapping > Pre-Processing > Issue Association > Email Threading.
Embedded Issue Key in Message ID
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