KIM 1.5: what's changing for your practice since late 2025

In day-to-day practice communication, KIM (Kommunikation im Medizinwesen — “secure mail in healthcare”) has become the standard route for secure mail between practices, hospitals, pharmacies and payers in Germany. With specification version KIM 1.5 (and its client counterpart KIM+ 1.5), the gematik released a set of noticeable changes in late 2025 — and some of them are not optional. Practices that don’t act risk outages in 2026. A quick overview of what you should know.

What it’s about

Behind the dry version numbers are three topics you’ll feel in daily work:

• Cryptography: switch from RSA to ECC. That affects which electronic health professional cards (eHBA) and SMC-B cards your practice works with.
• File sizes: attachments up to 500 MB are now possible. Until now things stopped at much smaller sizes — image-based reports often had to be sent in pieces.
• Multi-connector support: especially relevant for larger structures (hospitals, MVZs); normal practices benefit too in failover scenarios.

The RSA-to-ECC migration — the key detail

Until now your KIM system signed messages with RSA keys (from cards of generation G2.0). With KIM 1.5 the gematik moves to the more modern ECC method (cards of generation G2.1). Important:

• By the end of 2025, primary systems — including tomedo® through the KIM client module it uses — had to ensure they’re running the current KIM client module per specification KIM 1.5.2-9.
• During the transition year 2026, RSA and ECC run in parallel — that’s explicitly intended so that practices with G2.0 cards don’t get locked out overnight.
• From late 2026 onwards, receiving sides increasingly move to ECC only. Older G2.0 cards are phased out.

In practical terms: if your cards are due for renewal in the next 12–18 months anyway, you’ll receive the new G2.1 generation automatically. If your cards still have a long runtime, now is the time to check whether to trigger an early swap.

What changes day to day

Three points that an average practice will notice:

1. Larger attachments. Image reports, bundled findings, surgery reports with attachments — the things that have kept the practice fax line on life support — now travel through KIM in one piece.
2. Out-of-office. KIM+ 1.5 has an extended admin module that, among other things, enables out-of-office notes. Sounds mundane — feels golden on holiday.
3. Better security, better performance. ECC keys are shorter and faster to process than the old RSA keys. With many small messages a day, the difference is noticeable.

Where this fits with tomedo®

tomedo® integrates KIM via a certified client module. For the migration that means:

• Updating the KIM client module happens as part of the regular tomedo® updates — the technical orchestration is handled by zollsoft GmbH.
• What sits with the IT partner: making sure the connector update runs cleanly, the network is fit, cards are read correctly, and the connection to the TI infrastructure is stable.
• Before the update it’s worth running a backup restore test (see 3-2-1 backup) — if something goes sideways with the connector, you want a clean fallback.

With the upgrade to KIM+ 1.5, users can expect, among other things, sending of large files up to 500 MB, multi-connector support, and a new admin module for mailbox management including out-of-office notes.

What you should do now

1. Check card expiry. When does your eHBA / SMC-B run out? You’ll find this in the KIM admin area.
2. Check the update level. Which KIM client module version is running? Is tomedo® on a version that supports KIM 1.5.2?
3. Keep connector firmware up to date. A short joint maintenance window with us — or with your connector supplier — handles this.
4. Set up holiday cover. Who can access the KIM mailbox while you’re away? With the new admin module this is a matter of minutes — beforehand.

We’re happy to take the lead on the migration — on the hardware, network and connector side. The technical tomedo® configuration, as always, runs directly with zollsoft.