220.127.116.11. Author’s date of death is unknown
The author’s exact date of death is often unknown because they are either untraceable and you cannot therefore be sure whether they are still alive. Or the date of death cannot be precisely determined because the requisite information is missing. In such cases, the general 70-year term of protection (Art. 29 Para. 2 (b) CopA) (or the 50-year term of protection in the case of computer programs Art. 29 Para. 2 (a) CopA) cannot be calculated. When the term of protection of a work has expired and it can be assumed that the author has been dead for at least 70 years (or 50 years in the case of computer programs), then Art. 29 Para. 3 CopA applies. However, this assumption may not be made lightly. Rather, you “must be able to assume with a probability bordering on certainty that the author has already been dead for 70 years (or for 50 years in the case of computer programs). […] Such an assumption may be made if sufficient time has passed since the last signs of life from the author or may be expected due to the author’s year of birth taking into consideration the average lifespan upon expiry of the statutory deadline.” (Müller/Oertli – Reuter Gerster, Urheberrechtsgesetz, 2. edit., Art. 29 N 7a). For the calculation of the average lifespan, see also the Swiss Federal Statistic Office.