For buyers contracting authority
The mistake to avoid with 72267000 is mixing it up with Software support services (72261000). Support answers questions and resolves incidents; maintenance changes the code, patches it, and keeps it current. Many contracts blend both, so tag the primary CPV code by whichever dominates the statement of work.
Beyond that line the rule is simple: choose 72267000 when the contract keeps an existing system alive rather than creating something new. Bug fixes, version upgrades and support hours point here; a new feature set or a fresh application points to development (72262000).
One more trap: this code is for software, not hardware. Maintenance and repair of computer equipment is 50312000. Where a deal bundles software upkeep with licences or minor enhancements, keep it here as long as maintenance is the main purpose.