Under the Bharatiya Nyaya Sanhita (BNS), the definition of “murder” remains largely similar to the Indian Penal Code (IPC). However, the BNS simplifies language and structure, and may include updated provisions or exceptions. The core elements—intentional killing with malice—are unchanged.

Assuming you're referring to canadian criminal law as codified in the criminal code of canada (since there's no distinct body of law called the "BNS" that defines murder separately from canadian law).
The definition of murder has not fundamentally changed, but its interpretation and application have evolved over time through amendments and courts decision.
under section 229 of the criminals code of canada, murder is define as:
1.Intentionally; or
while meaning to cause bodily harm that they know is like to death
2.First degree v/s second degree murder (section 231)
First degree murder: planned and deliberate( like sexual assault or kidnapping).
Second degree murder: all other types murder that do not meet the criteria for first degree .

Has the change?
legally: The core definition of murder under canadian law hasn't drastically changed in the BNS or any where in canada.
Practically: The application, classification ,defences related to murder have evolved signification due to legislative refinements and judicial interpretation.