upgrade/v2306-User-Upgrade-Guide.md

@@ -14,10 +14,22 @@
 
 ## Rename
 
+### Function object: `patchPostProcessing` and `patchParticleHistogram`
+
+The Lagrangian function objects `patchPostProcessing` and
+`patchParticleHistogram` have been renamed as `particlePostProcessing` and
+`particleHistogram`, respectively, to enhance clarity and understanding.
+
 ## Configuration / Environment
 
 ## Input Dictionaries
 
+### Function object: `electricPotential`
+
+The calculation and output of the electric field (`E`) can be enabled or
+disabled by using the optional keyword `electricField`, replacing the previous
+keyword `writeDerivedFields`. Also, the name of the electric field (`E`)
+can now be specified using the new keyword `E`.
 
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