Update changelog in preparation for release

Author: dieriver

CHANGELOG.md

@@ -5,10 +5,15 @@ For more details refer to the [documentation](https://softwarequtech.github.io/S
 
 Upcoming
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-2025-07-15 (v4.0.1)
+2026-03-13 (v4.0.1)
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 - Migrated project specification to use modern TOML approach.
 - Tested working with Python versions 3.10, 3.11 and 3.12.
+- Added new SDK for easily creating SimulaQron applications. This new SDK allows to also create
+  client-server applications using event-based programming paradigm.
+- Updated the SimulaQron network configuration file format. This is done to align the network
+  configuration file with the data required by SimulaQron "native" mode and the "NetQASM" mode.
+- Updated documentation of most of the undocumented functions and to match the new developments.
 
 2021-11-18 (v4.0.0)
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