No Problem, enjoy your trip! 
And thanks for the link!
I tried myself, but I’m not a developer and I’m just puzzling here 
As writing it down might help, here is what I tried:
Generated code from the old script
var scriptExecution = Java.type('org.openhab.core.model.script.actions.ScriptExecution');
var zdt = Java.type('java.time.ZonedDateTime');
if (typeof this.timers === 'undefined') {
this.timers = [];
}
if (typeof this.timers['MyTimer'] === 'undefined' || this.timers['MyTimer'].hasTerminated()) {
this.timers['MyTimer'] = scriptExecution.createTimerWithArgument(zdt.now().plusSeconds(10),event, function (event) {
})
}
Generated code from the new timers
if (cache.private.exists('MyTimer') === false || cache.private.get('MyTimer').hasTerminated()) {
cache.private.put('MyTimer', actions.ScriptExecution.createTimer('MyTimer', time.ZonedDateTime.now().plusSeconds(10), function () {
}));
};
Code from the rule template:
if (typeof this.timers === 'undefined') {
this.timers = [];
}
if (typeof this.timers[{{input:timer_name}}] === 'undefined' || this.timers[{{input:timer_name}}].hasTerminated()) {
this.timers[{{input:timer_name}}] = {{utility:scriptExecution}}.createTimerWithArgument({{utility:zdt}}.now().{{field:duration_unit}}({{input:duration}}),event, function (event) {
{{statements:timer_statement}}
})
}
My try to adapt, but without any idea how to integrate the selector for private or shared cache
if (cache.private.exists[{{input:timer_name}}] === false) || cache.private.get[{{input:timer_name}}].hasTerminated()){
cache.private.put([{{input:timer_name}}] = {{utility:scriptExecution}}.createTimerWithArgument([{{input:timer_name}}] , ({{utility:zdt}}.now().{{field:duration_unit}}({{input:duration}}),event, function (event) {
{{statements:timer_statement}}
})
}
It all is way more complicated than I thought. Seems like I can’t even understand the Tutorial
I tried to setup a library, to get things started, but this doesn't even compile
uid: blocklibrary_test
tags: []
props:
parameters: []
parameterGroups: []
timestamp: Nov 11, 2023, 3:45:48 PM
component: BlockLibrary
config:
name: Block Library Reschedule with context test
slots:
blocks:
- component: BlockType
config:
args0:
- check: Number
name: duration
type: input_value
- name: duration_unit
options:
- - seconds
- plusSeconds
- - minutes
- plusMinutes
- - hours
- plusHours
- - days
- plusDays
- - weeks
- plusWeeks
- - months
- plusMonths
type: field_dropdown
- check: String
name: timer_name
type: input_value
- default: mail@demo
name: timer_statement
type: input_statement
colour: 0
helpUrl: https://openhab-scripters.github.io/openhab-helper-libraries/Guides/Event%20Object%20Attributes.html
inputsInline: true
message0: after %1 %2 do with %3 %4 and keep triggering event-context
nextStatement: ""
previousStatement: ""
tooltip: Schedules a new timer and will pass the event variable as argument to the timer, that you can reuse the initial event during timer execution (e.g. event.itemName)
type: timerWithInitialEvent
slots:
code:
- component: BlockCodeTemplate
config:
template: >
if (cache.private.exists[{{input:timer_name}}] === false || cache.private.get[{{input:timer_name}}].hasTerminated()){
cache.private.put([{{input:timer_name}}] = {{utility:scriptExecution}}.createTimerWithArgument([{{input:timer_name}}] , ({{utility:zdt}}.now().{{field:duration_unit}}({{input:duration}}),event, function (event) {
{{statements:timer_statement}}
})
}
toolbox:
- component: PresetInput
config:
fields:
TEXT: MyTimer
name: timer_name
shadow: true
type: text
- component: PresetInput
config:
fields:
NUM: 10
name: duration
shadow: true
type: math_number
I’ll get some good rest and try another day.
Is there any place where I can see the setup from current timers blockly library to start with?
I only found that and it doesn’t look like a blockly library at all to me.