The first-generation Petzl ZigZag (before 2019) can be used for SRT with the Chicane auxiliary brake and the Knee Ascent access system.
Petzl’s internal testing team has verified that the first generation ZigZag is compatible with the Chicane and is safe for climbing SRT. However, Petzl is warning users who climb with a first generation ZigZag and plan to use the Knee Ascent system.
The first-generation ZigZag does not have an auxiliary attachment hole for connecting the Knee Ascent system, as on the ZigZag 2019 and ZigZag Plus. By default, it is possible to attach the Knee Ascent to the connector between the ZigZag and Chicane, taking care not to interfere with the proper functioning of the system.
Read Petzl’s news release here; https://www.petzl.com/GB/en/Professional/Compatibility-of-the-first-generation-ZIGZAG-with-CHICANE-and-KNEE-ASCENT?ActivityName=Tree-care&fbclid=IwAR09H9I5kPKV1mPHH2x48k1l8qPATKW20chjnMjXS39HOZL4sMQNKZ1r88w