Update introduction.adoc (#22)

* Update introduction.adoc

Update intro (change dates...)

* Update introduction.adoc

Editorial changes.

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Co-authored-by: Jeremy Tandy <[email protected]>

transition-guide/sections/introduction.adoc

@@ -1,8 +1,8 @@
-== Introduction
+=== Introduction
 
-The WMO Information System 2.0 (WIS2) will be implemented according to the schedule provided in Figure 1. A one-year pilot phase will start at the end of 2022, with several countries collaborating in building the WIS2 infrastructure. Each Country will have a different role in the WIS2 framework and will implement a specific component.
+The WMO Information System 2.0 (WIS2) will be implemented according to the schedule provided in Figure 1. As planned and after a succesful pilot phase in 2023, WIS2 has entered its pre-operational phase from 1st January 2024. The operational phase of WIS2 will begin on 1st January 2025.
 
 .WIS2 implementation timeline
 image::images/wis2-timeline.png[WIS2 implementation timeline]
 
-According to the WIS2 implementation plan (see figure 1), the Global Telecommunication System (GTS) will be decommissioned by 2030, and National Meteorological and Hydrological Services NMHSs will use the WIS2 platform for data exchange. During the transition period, there will be a mix of centres operating WIS2 and WIS/GTS. Some of them will be running both data-sharing frameworks simultaneously, with the difficulties associated with maintaining two operational systems for the same purpose. Therefore, a transition plan will be developed during the pilot phase, taking into account the time necessary for Members to migrate to the new systems and reducing, at the minimum, the time of parallel operation of both systems for a Member.
+According to the WIS2 implementation plan (see figure 1), the Global Telecommunication System (GTS) will be decommissioned by 2033, and National Meteorological and Hydrological Services NMHSs will use the WIS2 platform for data exchange. During the transition period, centres will operate WIS2 and/or WIS/GTS. Some of them will need to run both data-sharing frameworks simultaneously for some time, for various reasons (eg. being an RTHs,...), with the difficulties associated with maintaining two operational systems for the same purpose. Therefore, and to make the transition as smooth as possible and to avoid unnecessary burden on all Members, a mechanisms including gateways have been defined. Gateways will operate in both directions between WIS2 and GTS. Consequently, there will be both GTS to WIS2 gateways and WIS2 to GTS gateways. This guide details the various aspects of the transition as well as the way Centres will gradually evolve from a pure WIS/GTS setup to a full WIS2 environment.