What the category reaches Annex III Class I (9), Art. 7(1), Art. 7(2), Art. 7(4)
Item 9 of Class I names "public key infrastructure and digital certificate issuance software". The focus is on the software that mints, signs, and manages digital certificates and the keys behind them: a certificate authority application, a registration authority, a certificate lifecycle manager, and an issuance server that answers enrolment requests.
It sits in Class I for the Article 7(2) reason: PKI primarily performs a function critical to the cybersecurity of other products, since trust in every certificate it issues rests on it. The binding scope is the technical description in the implementing act, so assess your product against that, not against the plain label.
Internal CA tooling and ACME servers Art. 7(1), Art. 7(4)
A common assumption is that only public, trusted certificate authorities are in view. That is too narrow. Software you supply that issues certificates for an internal or private PKI, and an ACME server that automates issuance, are certificate issuance software by function, whatever the trust anchor, where you place them on the market as a product.
The distinction to keep is between issuing certificates and merely consuming them. A product that requests, stores, or validates certificates is not itself PKI issuance software, and Article 7(1) confirms that integrating an issuance component does not, on its own, reclassify the surrounding product. Resolve close calls against Implementing Regulation (EU) 2025/2392, record the outcome, and until then treat the stricter Class I route as your working assumption.
Judgment call: Whether tooling that automates certificate issuance for a private PKI is "certificate issuance software" for item 9 is a judgment the implementing act settles; issuing differs from consuming.
What Class I changes: your conformity route Art. 32(1), Art. 32(2), Annex VIII
For a default-category product a manufacturer may self-assess under internal control (module A). For a Class I important product that choice narrows: internal control remains available only where you apply harmonised standards, common specifications, or a European cybersecurity certification scheme at assurance level at least "substantial", in full, to the relevant essential requirements.
Where you do not, or where no such standard yet exists, the product must go through EU-type examination plus conformity to type (modules B and C) or full quality assurance (module H), both involving a notified body. Plan for that lead time well before 11 December 2027.
Everything else is the ordinary manufacturer programme Art. 13, Art. 14, Annex I
Class I status changes the conformity route, not the substance. The essential cybersecurity requirements, vulnerability handling including a coordinated vulnerability disclosure policy, technical documentation, CE marking, and the reporting duties for actively exploited vulnerabilities and severe incidents apply to PKI software as they do to any product in scope. Protection of signing keys and issuance integrity carries particular weight here.