General Terms and Conditions

General Terms and Conditions of grommunio GmbH — Version: May 2026

1. Scope of application

These General Terms and Conditions ("GTC") shall apply to all offers and contracts of grommunio GmbH, Donau-City-Str. 7, 1220 Vienna ("grommunio") and its contractual partner ("Client"; grommunio and Client jointly the "Parties"), in particular for the provision of support and maintenance services as well as training ("Services"). These GTC shall also apply to future orders even if no express reference is made thereto.

The activities of grommunio consist in particular of the development of the grommunio Software, its distribution, and the provision of services in connection with its use. grommunio does not operate any data centre and does not provide hosting services.

The distribution and provision of services to customers of the Client ("End Customers") shall generally be carried out via the Client as the contractual partner authorized by grommunio. In this respect, grommunio shall exclusively maintain a contractual relationship with the respective Client; End Customers shall not be contractual partners of grommunio and shall have no direct claim to services provided by grommunio.

It is noted that the "grommunio Software" is an open source-based groupware product. The Client may download the community version of the grommunio Software free of charge and use and operate it independently in accordance with the applicable open source license terms. This shall apply both to productive use and to testing purposes within the Client's own infrastructure (at the Client's option on-premises or in a cloud environment). Unless expressly agreed otherwise, the grommunio Software itself and any rights of use thereto shall not form part of the subject matter of these GTC. Consequently, grommunio shall neither owe any performance with respect thereto nor assume any warranty or liability in this regard. The mere acquisition and use of the grommunio Software (including within the framework of a test subscription) shall not establish any entitlement to Services. grommunio shall only provide Services to the Client upon conclusion of a productive subscription in the form of a support package.

The content of offers or individual contracts shall take precedence over these GTC. Any deviations from these GTC shall only be binding for grommunio if they have been agreed in writing and duly signed. By submitting the contractual declaration (see Section 2 below), Client accepts these GTC. Contracts may only be concluded on the basis of these GTC. Client's general terms of business or purchase are hereby excluded for the present legal transaction and the entire business relationship, unless grommunio has expressly agreed to their validity in writing.

In the case of multiple contracts concluded at different points in time, the version of the GTC published on the grommunio website that is valid at the time the Client submits the contractual declaration shall become part of the contract in each case. Upon acceptance of the new GTC, such GTC shall also apply to the Client's existing contracts.

Contractual and business language is German. In the event of any discrepancy, inconsistency, or ambiguity between the German and the English language versions of the GTC, the German version shall prevail.

2. Offer, conclusion of contract

Product descriptions, provision of the Partner Portal and offers of grommunio do not constitute binding offers, but serve for the submission of a binding offer by the Client by placing an order. The contract shall only be deemed concluded when grommunio confirms the order after receipt thereof. Where technically feasible and provided, the contract may also be concluded digitally via the grommunio Partner Portal ("Partner Portal") by the Client registering in the Partner Portal and accepting these GTC.

Upon conclusion of the contract, a contractual relationship shall be established exclusively between grommunio and Client. Any terms and conditions in the Client's order that deviate from the offer or are not regulated in the offer of grommunio shall not become part of the contract unless they are expressly confirmed by grommunio in writing.

3. Services

The type and scope of the Services agreed with the Client shall be set out in the offer concluded between the Parties, which specifies the respective support package and/or any additional Services exceeding such scope. The support packages grommunio Basic, grommunio Plus, grommunio Business and grommunio Enterprise are conclusively described in Annex 1 to these GTC. In addition, or — depending on the service description — within this framework, grommunio may offer further Services, which are based on individual offers to the Client and shall be remunerated in accordance with the applicable hourly rates of grommunio.

All Services under this contract shall be provided only for the most recent version of the grommunio Software available at the time of the conclusion of the contract. grommunio shall not provide any Services for previous versions or outdated program versions of the grommunio Software.

Services that are not listed in Annex 1 in the respective service category of the relevant support package are not included in the subject matter of the contract and are therefore not owed by grommunio. For the avoidance of doubt, it is hereby clarified that, in particular, the following Services are not included in any of the support packages:

• Integration of the grommunio Software at the Client's site and provision of standardized setup or installation manuals*
• Conversion of the grommunio Software to a different hardware system*
• Creation of individual programs*
• Training by telephone and remote maintenance*
• Extension of the grommunio Software according to the special wishes and requirements of the Client*
• Support and information regarding other software and hardware not related to the grommunio Software*
• Elimination of malfunctions and damage caused by improper handling on the part of the Client or its End Customers, in particular by unauthorized modifications to the software, by the actions of third parties or by force majeure*
• Elimination of malfunctions and damage caused by environmental conditions at the location of the Client's or its End Customers' hardware, by faults or non-performance of the power supply, by faulty hardware or by other effects for which grommunio is not responsible*
• Removal of computer viruses, malware, Trojans or other malicious software*

* These services can — at grommunio's own discretion — be commissioned from grommunio by the Client at the Client's expense.

grommunio shall be free in determining the manner of performance of its Services and shall not be subject to instructions. In the provision of Services, grommunio shall exercise reasonable care but shall not owe any specific result. grommunio shall be entitled to have the contract performed (in whole or in part) by expert employees or commercial/freelance cooperation partners/subcontractors and to use artificial intelligence.

grommunio continuously optimizes and further develops its Services. grommunio therefore reserves the right to make any new functionalities available to the Client on a voluntary basis. However, grommunio shall not be obliged to do so without separate engagement.

4. Partner Portal and Subscriptions

Upon registration in the Partner Portal, the Client automatically receives a not-for-resale subscription ("NFR Subscription"). This serves the Client as a strategic partner to perform back tests and to familiarize itself with the grommunio Software. The NFR Subscription corresponds to the scope of grommunio Basic and entitles the Client to create the users required for its internal purposes. The NFR Subscription is granted exclusively to the Client; use and support in relation to End Customers are not covered.

After registration in the Partner Portal, grommunio may, at its own discretion, offer the Client a one-time onboarding session via an online call for the introduction to the grommunio Software and Services. The Client shall have no entitlement to such onboarding; it shall be at the sole discretion of grommunio whether such onboarding is offered. In any case, the onboarding shall be limited to a maximum duration of 45 minutes.

After the Client has completed registration in the Partner Portal — and, if applicable, the onboarding — grommunio will enable the Client to create paid subscriptions via the Partner Portal for the use and support of the grommunio Software for End Customers and to provision such subscriptions for its End Customers ("Productive Subscription"). Only within a Productive Subscription shall the Client receive a supported version of the grommunio Software and Services in accordance with the concluded support package for its End Customers (see Section 3 above).

In addition, the Client may receive a free, time-limited subscription for purposes of internal evaluation, testing and demonstration vis-à-vis End Customers ("Test Subscription"). This Test Subscription serves the evaluation and testing of the grommunio Software at the End Customer and is not intended for internal productive use by the Client. Productive use by the End Customer within the framework of the Test Subscription shall be permitted solely during the test period for evaluation or testing purposes and shall not include any support in accordance with Annex 1 and Annex 2. For use and support after the agreed test phase pursuant to Section 10 or in the event of any further productive use, the conclusion of a paid Productive Subscription shall be required.

5. Performance dates

The type and timing of the provision of Services as well as any other schedule arrangements may be agreed in the contract or, after conclusion of the contract, orally or in writing between the Parties (e-mail shall suffice). grommunio shall endeavour to meet any notified dates for the provision of Services as closely as possible. The Client shall not be entitled to any damages or other claims arising from any non-compliance with deadlines or dates.

Hindrances to performance for which grommunio is not responsible shall entitle grommunio to postpone the provision of Services and/or any dates agreed in writing for the duration of the hindrance and an appropriate start-up period. This shall also apply if such events occur during an existing delay. It is irrelevant whether these circumstances occur with the Client, with grommunio itself or with one of its suppliers / subcontractors.

6. Service Levels

Maintenance services within a support package include general bug fixes of the grommunio Software as defined in the Service Level Agreement (Annex 2) and the respective support package. Unless agreed otherwise in the respective support package, updates or upgrades are not included. § 7 of the Austrian Consumer Warranty Act ("VGG") is expressly excluded. Maintenance services are governed by the Service Level Agreement in accordance with Annex 2.

7. Cooperation obligations of the Client

Proper performance by grommunio requires adequate, timely and high-quality cooperation by the Client. The Client undertakes to provide grommunio with all necessary organizational and operational information and documents relating to the respective offer in a timely manner and free of charge. Upon request by grommunio, the Client shall approve Services.

The Client is entitled to integrate the grommunio Software at End Customers. For this purpose, the Client shall define the End Customer's requirements directly with the End Customer. The Client shall ensure in its contracts with its End Customers that no contractual relationship is established between grommunio and the End Customer. The Client shall be obliged to impose on its End Customers, mutatis mutandis, the obligations incumbent upon it and the restrictions set out in these GTC and in any applicable license terms of the grommunio Software. The Client shall ensure that the End Customer cannot assert any direct claims for Services against grommunio and shall indemnify and hold grommunio harmless in this respect. The Client shall be solely responsible for the integration of the grommunio Software at the End Customer.

The Client acknowledges that the grommunio Software is based on Linux. Accordingly, integration and migration require appropriate technical knowledge, in particular in the Linux environment. The Client warrants that it has the necessary knowledge and resources.

The Client shall have an internet connection that complies with the technical standards at the time the Services are provided (minimum speed "ADSL"), if the Client wishes to make use of the corresponding remote support within the scope of the support offering. Furthermore, the Client shall be responsible, at its own cost and risk, for ensuring, maintaining, servicing and keeping operational all required infrastructure and system prerequisites necessary to use the grommunio Software.

The Client shall designate a system manager who shall be the contact person of grommunio for all questions relating to the performance of this contract. In this case, the Client shall ensure that the system manager is knowledgeable and is able to make decisions relating to this contract independently or arrange for such decisions to be made in a timely manner.

Error correction shall be carried out within the framework of the support options provided, depending on the support package concluded and the applicable Service Level Agreement (Annex 2). The Client shall ensure that remote maintenance access secured in accordance with the current state of the art is set up and made available to grommunio at least during maintenance hours. Furthermore, the Client shall keep the technical facilities required for the performance of the maintenance work, such as power supply, telephone connection and data transmission services, ready for operation and shall make them available to grommunio free of charge to a reasonable extent. Remote maintenance software recommended by grommunio shall be installed by the Client at its own expense upon first request by grommunio.

It shall be the responsibility of the Client to perform and verify regular data backups and to properly maintain and service the system environment of the grommunio Software.

grommunio shall not be obliged to verify the quality or correctness of the Client's contributions. If delays and/or additional effort arise due to the Client's failure to fulfil the obligations set out herein, grommunio shall be entitled — without prejudice to any other statutory rights — to request adjustments to the schedule and/or the agreed remuneration. The remuneration for any additional effort shall be based on the hourly rates of grommunio applicable at that time.

The Client undertakes not to disclose any login usernames, passwords, materials or links to third parties unless such disclosure is strictly necessary for the performance of the contract between the Client and its End Customers.

8. Rights of use

The Parties acknowledge that all rights, in particular exclusive exploitation rights, rights of adaptation and moral rights to intellectual property, which a Party already owns prior to the conclusion of the contract and makes available for the provision of Services, shall remain with the respective Party. In particular, grommunio shall retain all exclusive rights or rights of use to the grommunio Software and to the content provided within the scope of the Services, such as, for example, software, programs, program listings, tools, documentation, protocols, drawings, training materials or other (protected or unprotected) work results.

The Client shall receive the non-exclusive, non-sublicensable and non-transferable right to use the results and content of the Services solely for internal company use for the purpose defined in the contract. The Client shall further receive the non-exclusive, non-transferable and non-sublicensable right to use the Partner Portal for the duration of the contract. All other rights of exploitation or use shall remain with grommunio, irrespective of whether the result of the Services or the content was developed solely by grommunio or jointly by the Parties.

The use of the results and content of Services rendered for companies affiliated with the Client or other third parties requires a separate, prior written agreement. Subject to a separate written agreement, the Client shall in principle not be entitled to make the results or content of the Services available to any third parties, in part or in full, against payment or free of charge, or to transfer or rent them. However, if provided for in a corresponding contractual agreement (e.g. in the offer or in an individual contract), the Client shall be entitled to make the results of the Services available to authorized third parties (e.g. End Customers named therein), in which case such third parties shall be entitled to use them to the same extent as described herein.

grommunio warrants that it is not aware that the Services infringe the rights of third parties. The Client shall have no further claims in this respect.

9. Prices, taxes and fees

The remuneration and any specific payment terms for the Services shall be set out in the offer. All prices are stated in Euro exclusive of statutory value added tax, fees or public charges. The list prices valid at the time of the conclusion of the contract shall apply, unless expressly agreed otherwise.

The Services rendered by grommunio shall be invoiced on the basis of the actual expenditure immediately after the Services have been rendered or on a monthly basis in the case of a contract term of more than one month. The Client agrees to receive invoices by e-mail to the e-mail address provided by the Client. The Client waives the right to receive invoices by post. The costs for travel, daily and overnight allowances shall be invoiced to the Client separately according to the rates agreed in each case. Travel times shall be deemed to be working time.

The invoices issued by grommunio are payable upon receipt of the invoice without any deduction and free of charge. For partial invoices, the terms of payment specified for the overall order shall apply analogously. The payment term shall be 14 days from the date of the invoice and its transmission to the Client. Any difficulties in the transfer of invoice amounts shall be borne by the Client. It is exclusively at the discretion of grommunio to determine to which of several claims incoming payments are credited. Within the same claim, incoming amounts shall first be credited to costs, then to interest and finally to capital.

In the case of orders comprising several units of Services (e.g. training courses, implementation in partial steps), grommunio shall be entitled to issue an invoice after each individual Service has been rendered.

The remuneration for Services agreed in the respective contracts, offers and price lists shall be subject to value adjustment in accordance with the Consumer Price Index – Revision 2020 (or any index replacing it) published by Statistics Austria. Fluctuations of the index figure of up to and including 3 percentage points, whether upwards or downwards, shall be disregarded. The first index adjustment shall take place on 1 January of the second contractual year and thereafter each time the applicable tolerance range is exceeded, whether upwards or downwards. In each case, the first index figure lying outside the respective tolerance range shall form the basis for the calculation of the new tolerance range. In the course of the price adjustment, the Client shall receive an updated price list reflecting the new standard prices. The new, updated price list shall replace all previously valid price lists.

Compliance with the agreed payment dates shall constitute an essential condition for the provision of the Services. If the Client is in default with payment, grommunio shall be entitled to:

• postpone the fulfilment of its own obligations, including those to be rendered to the Client under another title, of any kind whatsoever, until payment has been made and to withhold the Services or to interrupt or discontinue the provision of the Services;
• demand payment of the entire outstanding price or remuneration; however, this shall only apply if the Client is in default with payment of two invoices;
• claim security, also for claims not yet due, from all agreements at grommunio's discretion;
• charge interest on arrears from the due date at the rate customary for overdraft facilities, but at least 12% interest per annum, as well as compound interest at a rate of 4% per annum;
• withdraw from the contract if a reasonable grace period is not met.

The Client shall not be entitled to withhold payments due to guarantee, warranty or other claims or complaints. The Client shall not be entitled to offset any claim it may have against grommunio against a claim of grommunio (prohibition of set-off).

10. Contract period and right of termination

The subscription underlying the contract shall be concluded for the duration agreed in the offer or individual contract. Unless otherwise agreed, the following shall apply:

The Test Subscription shall be concluded for a fixed term of up to three (3) months and shall commence upon its creation in the Partner Portal ("Test Phase"). It shall automatically expire upon expiry of the agreed Test Phase without the need for separate termination. After the Test Phase, the Client may switch to a paid Productive Subscription in accordance with the agreed support package.

The term of the Productive Subscription shall be determined in accordance with the respective offer and shall typically be between twelve (12) and thirty-six (36) months ("Contract Year"). The Productive Subscription may be terminated in writing by either Party at the end of each Contract Year subject to a notice period of four (4) weeks; otherwise, it shall automatically renew for a further Contract Year in each case.

The NFR Subscription shall be concluded for a fixed term of one (1) year and shall commence upon registration in the Partner Portal. The NFR Subscription shall automatically renew for a further term of one (1) year in each case, provided that the Client has at least one active Productive Subscription at the end of the respective term.

The right to extraordinary termination for good cause shall remain unaffected. grommunio shall be entitled to extraordinary termination in particular in the following cases:

• in the event of repeated or serious breach of the contract or of these GTC;
• if the Client repeatedly obtains Test Subscriptions over a period of at least 12 months without having established at least one active paid Productive Subscription in the Partner Portal;
• in the event of repeated unjustified or incorrect error reports by the Client;
• in the event of repeated support requests by the Client without a covering Subscription, after prior warning and a further breach by the Client;
• in the event of the Client's acquisition by a competitor of grommunio;
• in the event of default on the part of the Client in the fulfilment of contractual obligations after grommunio has set a reasonable grace period of at least 14 days;
• in the event of a breach by the Client of any contractual ancillary obligations;
• if termination of the contract is indispensable to avert personal or economic disadvantages for grommunio.

Furthermore, grommunio may permanently deactivate the Client's account in the Partner Portal if the Client has not logged into the Partner Portal for an extended period of time, but at least 12 months, or has not maintained any active Productive Subscriptions during such period. Prior to deactivation, grommunio shall inform the Client of the intended deactivation by e-mail. Unless the Client expressly objects to the deactivation within 14 days of receipt of the notification — whereby such notification shall explicitly refer to the effect of any silence as well as the relevant objection period — grommunio shall be entitled to delete the account and all related data of the Client.

In the event of the opening of insolvency proceedings against the Client's company, grommunio reserves the right to amend the terms of payment or performance, in particular to switch to performance against payment or to require advance payment from the Client; in the event of an advance payment obligation, grommunio shall only perform its Services against the provision of a security by the Client.

Cancellations by the Client shall only be possible with the written consent of grommunio. If grommunio agrees to a cancellation, it shall be entitled to charge a cancellation fee in the amount of 30% of the not yet invoiced order value of the overall project, in addition to the Services rendered and costs incurred.

11. Warranty, maintenance, modifications

With respect to Services, grommunio warrants that

• the provision of Services is carried out in accordance with the state of the art;
• a high standard of care and quality is applied in the performance of the contract;
• only competent personnel are employed in the provision of Services.

The Client acknowledges that it has tested and is familiar with the functionality of the grommunio Software within the framework of the NFR Subscription. grommunio therefore does not make any performance commitments or guarantees (with the exception of the response times set out in Annex 2 within the framework of the Service Level Agreement). If a responsibility for success is expressly agreed in the contract, grommunio warrants that the Services rendered comply with the contractually agreed specifications in all aspects material to the Client and are not affected by defects which significantly impair or reduce their suitability. grommunio does not warrant that the functions contained in the results of the Services will operate uninterruptedly and error-free in a combination selected by the Client (unless specified in advance by test cases provided by the Client). Such an assurance also cannot be given if changes occur in the system environment. To the extent permitted by law, the rectification of defects shall be carried out exclusively in accordance with the provisions set out in the Service Level Agreement (Annex 2).

The Client shall be solely responsible for the selection of the Services, the specific use of the grommunio Software and the technical operating environment. The Client shall bear the risk that the Services meet its requirements. grommunio assumes no warranty in particular for the availability, integrity, security or compatibility of the grommunio Software when using versions that are not or no longer supported. Any warranty for defects due to hardware or operating system errors is likewise excluded.

Notwithstanding any applicable periods, warranty claims shall in any case become statute-barred after one year from the date of performance of the Services or from the date of acceptance (if such acceptance is stipulated in the offer). The burden of proof for the existence of a defect at the time of the provision of the Services or acceptance shall lie with the Client. Any liability of grommunio for consequential damage caused by defects on the grounds of compensation for damages is excluded.

Costs for assistance, misdiagnosis and elimination of errors and faults for which the Client is responsible as well as other corrections, changes and additions shall be carried out by grommunio against payment in accordance with the currently valid price list. grommunio assumes no warranty for errors, malfunctions or damage resulting from changes to the Services by the Client itself or by third parties commissioned by the Client, improper operation, lack of technical expertise in the Linux environment, modified operating system components, interfaces and parameters, the use of unsuitable organizational resources and data carriers, insofar as such are prescribed, abnormal operating conditions (in particular deviations from the installation and storage conditions) as well as damage in transport and the like.

If, despite written notice and the setting of a reasonable grace period of at least 14 days, grommunio fails to comply with its response obligations under the SLA (Annex 2), the Client may terminate the contract extraordinarily for good cause. The response times defined in the SLA relate exclusively to the acceptance and processing of error reports and not to the duration of the rectification of defects. A specific time for rectification is not owed. In particular, delays in remedying defects shall not constitute grounds for termination insofar as they are attributable to the complexity of the systems, dependencies on third-party software or causes beyond the control of grommunio.

Insofar as the subject of the order is the modification or addition to existing programs, the warranty shall relate solely to such modification or addition. The warranty for the original program shall not be revived thereby. For the avoidance of doubt, no warranty or liability shall be assumed for software modules not developed by grommunio. The warranty claims set forth herein are conclusive. Notices of defects, warranty inspections and the implementation of warranties shall not interrupt the warranty and limitation periods.

12. Liability

grommunio shall only be liable for damages caused within the scope of the performance of the contract if grommunio or the vicarious agents acting for grommunio can be proven to have acted intentionally or with blatant gross negligence. Claims for damages in cases of slight as well as normal gross negligence are excluded. This exclusion shall not apply to personal injury or product liability claims. The burden of proof for the existence of blatant gross negligence or intent shall lie with the Client.

Furthermore, liability for indirect damage, consequential damage and collateral damage, including loss of profit, loss of turnover and interest, legal costs and damage resulting from loss of data or use of data, is excluded. In particular, grommunio shall not be liable for any limitations in the functionality or performance of the grommunio Software insofar as such limitations are attributable to (i) improper implementation or (ii) insufficient technical expertise — in particular in the Linux environment — within the Client's area of responsibility. In such cases, the Client shall be liable for all damages resulting therefrom and shall indemnify and hold grommunio harmless in this respect.

Claims for damages must be asserted within one year from the date of performance of the Services, failing which such claims shall be forfeited.

13. Loyalty

The Parties undertake to act loyally towards each other. They shall refrain from any solicitation and employment, also via third parties, of employees of the other Party who have worked on the performance of the contracts for the duration of the contract and for a period of 12 months thereafter. The Party in breach of this provision shall be obliged to pay liquidated damages in the amount of one annual salary of the employee of the other Party.

14. Data protection and confidentiality

The Parties shall, in accordance with the applicable data protection regulations, ensure compliance with the obligations relating to data protection and data secrecy and shall oblige their employees to comply with these obligations. These GTC include as an integral part the terms for data processing pursuant to Art 28 of the General Data Protection Regulation ("GDPR") set out in Annex 3. In this context, grommunio shall act as a processor for the Client. For this purpose, the Client hereby agrees to Annex 3.

The Parties undertake to maintain confidentiality with respect to all matters and trade and business secrets that become known in connection with the performance of the contract, to use such information solely for the purpose of performing the contract and not to make it available to third parties, and to impose the same confidentiality obligations on their employees and vicarious agents. Upon request of the disclosing Party, confidential information shall be returned to the disclosing Party or destroyed after termination of the contract. The obligation to maintain trade and business secrets shall apply for an unlimited period, including after the termination of the business relationship. Exceptions shall apply in cases where there is a statutory obligation to disclose information, where the confidential information was already publicly available without breach by the receiving Party, was already known to the receiving Party at the time of the conclusion of the contract, or becomes known to the receiving Party without any obligation of confidentiality.

15. Changes to the GTC

grommunio shall be entitled to amend these GTC at its own discretion at any time. Amendments to the GTC shall be notified to the Client by e-mail to the e-mail address provided by the Client prior to their entry into force. Unless the Client expressly objects to the amendment within 14 days of receipt of the notification — whereby such notification shall explicitly refer to the effect of any silence as well as the relevant objection period — the amendment shall be deemed accepted. In the event of an objection, the previous GTC shall continue to apply, unless grommunio terminates the contract with the Client within 14 days of receipt of the objection.

16. Miscellaneous

The place of performance for all transactions shall be the registered office of grommunio, unless expressly agreed otherwise. Should individual provisions of this contract be or become invalid, this shall not affect the validity of the remaining provisions of the contract. The Parties shall cooperate in a spirit of partnership to find a provision that comes as close as possible to the invalid provision. The Client grants grommunio the right to name the Client as a reference after conclusion of the contract, unless the Client objects.

17. Final provisions

All disputes arising out of or in connection with the contracts concluded between the Parties shall be governed by Austrian law, excluding its conflict of law rules and the United Nations Convention on Contracts for the International Sale of Goods (CISG). For all disputes, the Commercial Court of Vienna shall have exclusive jurisdiction. All material communications shall be made in writing or by e-mail and shall be addressed to the contact person specified in the offer of grommunio. Notifications by the Client relating to notices of defects, the setting of grace periods due to default, or the amendment or termination of the contractual relationship with grommunio shall only be legally effective if duly signed by the Client.