How to change snapcraft.yaml to build on snapcraft core18?

Hi,
my original snapcraft.yaml is for current Meteor 1.6 based wekan, and building it works:
https://github.com/wekan/wekan/blob/devel/snapcraft.yaml
I’m trying to modify it to build on core18 or newer (if possible), because I use Ubuntu 19.10 for Docker, but it does not work:
https://github.com/wekan/wekan/blob/meteor-1.8/snapcraft.yaml
Currently I’m getting these errors when trying various modifications:

wekan@wekan-64:~/repos/wekan$ sudo snap logs -f multipass
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:119 read_stream(type = 0, timeout = -1): 
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:137 read_stream(): num_bytes = 10
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:137 read_stream(): num_bytes = 0
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:119 read_stream(type = 0, timeout = -1): 
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:137 read_stream(): num_bytes = 13
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:137 read_stream(): num_bytes = 0
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:119 read_stream(type = 0, timeout = -1): 
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:137 read_stream(): num_bytes = 19
2019-06-29T18:20:46Z multipassd[3237]: /build/multipass/parts/multipass/src/src/ssh/ssh_process.cpp:137 read_stream(): num_bytes = 0
2019-06-29T18:20:46Z multipassd[3237]: Shutdown request delayed for 10 minutes
^C
wekan@wekan-64:~/repos/wekan$ sudo snapcraft clean
Failed to load plugin: properties failed to load for wekan: Additional properties are not allowed ('node-packages', 'node-engine' were unexpected)
wekan@wekan-64:~/repos/wekan$ nano snapcraft.yaml
wekan@wekan-64:~/repos/wekan$ sudo snapcraft cleanbuild --arch=amd64
Issues while validating snapcraft.yaml: 'adopt-info' is a required property or 'version' is a required property
  • What should be modified to make it work?
  • What is the syntax for newest snapcraft?
  • Is it possible to build snap using Ubuntu 19.10 as base?

Current failing build log is here:
https://launchpadlibrarian.net/431093911/buildlog_snap_ubuntu_bionic_amd64_wekan-meteor-1.8_BUILDING.txt.gz

It looks like they might have moved defining dependencies to package.json…

To build against core18 you need only specify:

base: core18

No, this is not possible, because there is no core19 or core19.10 base snap.

What version of snapcraft are you using?

On Ubuntu 19.10 I use snapcraft 3.6. In above config is text

base: core18

but it does not work, it produces above errors. I don’t know how to modify above snapcraft.yaml to get it working with core18.

My current working snapcraft.yaml is here, it is built by snap build service:
https://github.com/wekan/wekan/blob/devel/snapcraft.yaml