ical crashs every few months

[irrlicht]

kopano-ical crashs

code_te020-09-27T21:22:52.924605: [kopano-ical|T601] [info   ] Accepted connection from ***.***.***.***:50324
2020-09-27T21:22:52.930394: [kopano-ical|T29684] [debug  ] New Request
2020-09-27T21:22:52.930463: [kopano-ical|T29684] [debug  ] Receiving headers:
2020-09-27T21:22:52.930497: [kopano-ical|T29684] [debug  ] < ^V^C^A^B
2020-09-27T21:22:52.930523: [kopano-ical|T29684] [debug  ] < <8C>^BWk<C8><DB>^H<AA>6kT<B4>R<CD>͚<E0><DD><C9>^?
2020-09-27T21:22:52.930547: [kopano-ical|T29684] [debug  ] < <C0>       <C0>^S<C0>^T
2020-09-27T21:22:52.930567: [kopano-ical|T29684] [debug  ] < ^A
2020-09-27T21:22:52.935044: [kopano-ical|T29684] [crit   ] ----------------------------------------------------------------------
2020-09-27T21:22:52.935071: [kopano-ical|T29684] [crit   ] Fatal error detected. Please report all following information.
2020-09-27T21:22:52.935294: [kopano-ical|T29684] [crit   ] kopano-ical 10.0.6
2020-09-27T21:22:52.935371: [kopano-ical|T29684] [crit   ] OS: Debian GNU/Linux 9 (stretch) (Linux 4.9.0-13-amd64 x86_64)
2020-09-27T21:22:52.935399: [kopano-ical|T29684] [crit   ] Thread name: kopano-ical
2020-09-27T21:22:52.935422: [kopano-ical|T29684] [crit   ] Peak RSS: 154208
2020-09-27T21:22:52.935449: [kopano-ical|T29684] [crit   ] Pid 601 caught SIGABRT (6), out of memory or unhandled exception, traceback:
2020-09-27T21:22:52.935471: [kopano-ical|T29684] [crit   ] Backtrace:
2020-09-27T21:22:52.936175: [kopano-ical|T29684] [crit   ] f0. /usr/lib/x86_64-linux-gnu/libkcutil.so.0(+0x4f1f0) [0x7f8759e651f0]
2020-09-27T21:22:52.936201: [kopano-ical|T29684] [crit   ] f1. /usr/lib/x86_64-linux-gnu/libkcutil.so.0(+0x35c36) [0x7f8759e4bc36]
2020-09-27T21:22:52.936225: [kopano-ical|T29684] [crit   ] f2. /usr/lib/x86_64-linux-gnu/libkcutil.so.0(+0x35e79) [0x7f8759e4be79]
2020-09-27T21:22:52.936240: [kopano-ical|T29684] [crit   ] f3. /lib/x86_64-linux-gnu/libpthread.so.0(+0x110e0) [0x7f87597ad0e0]
2020-09-27T21:22:52.936258: [kopano-ical|T29684] [crit   ] f4. /lib/x86_64-linux-gnu/libc.so.6(gsignal+0xcf) [0x7f875609ffff]
2020-09-27T21:22:52.936271: [kopano-ical|T29684] [crit   ] f5. /lib/x86_64-linux-gnu/libc.so.6(abort+0x16a) [0x7f87560a142a]
2020-09-27T21:22:52.936287: [kopano-ical|T29684] [crit   ] f6. /usr/lib/x86_64-linux-gnu/libstdc++.so.6(_ZN9__gnu_cxx27__verbose_terminate_handlerEv+0x15d) [0x7f87569b80ad]
2020-09-27T21:22:52.936299: [kopano-ical|T29684] [crit   ] f7. /usr/lib/x86_64-linux-gnu/libstdc++.so.6(+0x8f066) [0x7f87569b6066]
2020-09-27T21:22:52.936316: [kopano-ical|T29684] [crit   ] f8. /usr/lib/x86_64-linux-gnu/libstdc++.so.6(+0x8f0b1) [0x7f87569b60b1]
2020-09-27T21:22:52.936329: [kopano-ical|T29684] [crit   ] f9. /usr/lib/x86_64-linux-gnu/libstdc++.so.6(+0x8f2c9) [0x7f87569b62c9]
2020-09-27T21:22:52.936345: [kopano-ical|T29684] [crit   ] f10. /usr/lib/x86_64-linux-gnu/libstdc++.so.6(_ZSt24__throw_out_of_range_fmtPKcz+0xf5) [0x7f87569deb85]
2020-09-27T21:22:52.936358: [kopano-ical|T29684] [crit   ] f11. /usr/sbin/kopano-ical(+0x27bae) [0x55774bb93bae]
2020-09-27T21:22:52.936374: [kopano-ical|T29684] [crit   ] f12. /usr/sbin/kopano-ical(+0x9b06) [0x55774bb75b06]
2020-09-27T21:22:52.936387: [kopano-ical|T29684] [crit   ] f13. /usr/sbin/kopano-ical(+0xac2c) [0x55774bb76c2c]
2020-09-27T21:22:52.936402: [kopano-ical|T29684] [crit   ] f14. /lib/x86_64-linux-gnu/libpthread.so.0(+0x74a4) [0x7f87597a34a4]
xt