Hi @diabolik75 - Make sure you are using the installation instructions found when clicking on the package icon in the Launch environment you are working on. For more information on registering the Adobe Analytics extension see: Adobe Analytics - Adobe Experience Platform SDKs
Hi laetizia_2018 - I'm moving this topic the analytics forum to hopefully answer your questions on how the backdate session options would affect server calls.
Hi Tejas - If you are doing native development, you want to look at the Adobe Experience Platform SDK (New 5.x) , or The Adobe Mobile Marketing SDK (4.x). Overview - Adobe Experience Platform SDKs Download Mobile SDKs and Tools
We are currently working on documentation to help support migrating from Adobe Mobile SDK v4.x to the Adobe Experience Platform SDKs + Adobe Launch. Let us know what questions you have about this process.