I of course do not know your specific usage and requirements, but Berlin-based OpenProject might be a suitable and mature Jira-alternative for you - in addition to being outside US jurisdiction their services are available both on-prem/self-hosted and cloud-based.
Sad news. 'In Our Time' episodes are actually timeless, I am frequently amazed by the quality of episodes from over twenty years ago.
Frankly, I believe that instead of finding a new presenter, the BBC could be retire the whole series and its legend. Let the new presenter start a new series, even if the set-up remains the same (including having further discussions with a cup of tea after the radio time limit has ended)
Ironically, stating this at the beginning of telegram would precisely cause what it seeks to prevent (vulnerability to known plaintext attacks).
Which makes me wonder: how many permutations of this rule could be conceived (and needed) that on the one hand would keep the point clear to the receiver, but on the other hand prevent such attacks?
In any case the best option is to not have (to repeat) this rule inside messages.
They even have a specific Jira-migration tool: https://www.openproject.org/docs/installation-and-operations...